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1. Introduction

The present article intends to clarify the concept of bibliographical control, to illuminate its main functions, to briefly describe its history in practice, and to survey the criticism, debate and different theoretical views associated with this practice. An underlying perspective throughout the article is to illuminate two conflicting philosophical approaches: positivism and pragmatism and their implicit influence on theory as well as practice.

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1.1 The concept and idea of bibliographical control

Bibliographical control means making useful documents/information resources findable for those who might need them, but have no, or insufficient, knowledge about their identity. The present article is based on a view that comes close to a definition provided by Pearson (2010, 523):

[B]ibliographical control. The concept of having a comprehensive and searchable listing of the entire published output in a particular field [or in a particular country or by a particular author or other formal demarcations].

The term is today often used as a synonym for information organization (or bibliographical organization or knowledge organization, KO) and for the process of describing information resources (documents) and providing name, title, and subject access to the descriptions (see Chan and Salaba 2016, 13-14; Joudrey, Taylor and Wisser 2018, 7; Library of Congress 2008 [1]; Maxwell 2017 [2]; Miksa 2013 and Wikipedia 2023 [3]). This is, however, an unfortunate way of defining the term as it focused more on document description (or cataloging or organization) and less on the aim of providing control over available documents. As Wilson (1968, 3) wrote:

What we see as problems of control, others have seen as problems of organization […]. But not all the problems of bibliographical organization are equally important in a discussion of bibliographical control, and many discussions in the enormous literature of bibliographical organization will go unnoticed here.

Therefore, this article focusses on the aims of providing control over documents, which has much to do with coverage of bibliographic databases. It will not go deeply into the issues of → cataloging rules, document description standards, → metadata, and the like, although this use of the term bibliographic control deviates somewhat from how the term is mostly used today. The two issues are related, and as we shall see later, a database like Google Scholar may have a better coverage than MEDLINE, but may still be less useful, because documents are less well described and represented in Google Scholar.

What is bibliographic control, and what is the purpose of obtaining it? Wilson also illuminated this, writing (ibid, 4):

Bibliographical control is a form of power, and if knowledge itself is a form of power, as the familiar slogan claims [4], bibliographical control is in a certain sense power over power, power to obtain the knowledge recorded in written form.

When academic students, professionals or researchers write papers, they are expected to build their papers on information in other papers, and to provide references to them. To do so, they need to know about the relevant sources, and ideally, they need to identify what Wilson (1968, 22) called “the best textual means to one's end”, i.e., the most important sources. In academia, this is almost a matter of course, but also for non-academic tasks available knowledge should be utilized, and thus also often depend on bibliographic control. The need is, however, most directly and explicit related to academic writing tasks.

Because relevant documents need not be textual, we rephrase Wilson's goal to “the best documents or the best information resources to one's end”. As discussed further in this article, no library or information system can guarantee such an ideal performance, but they can serve users approaching this goal, and this is what bibliographical control is about: to help users approach the goal of finding the documents most relevant for solving their task.

Bibliographical control is often understood as control over what has been published, a control that makes it possible in principle to overview what has been published. It may also be about unpublished documents, for example unpublished theses and other so-called “gray literature”. A new tendency is to include "data" (i.e., → data documents), see Schöpfel et al. (2021). Higgins and Green (2009 and later editions) explicitly recommend including “gray literature” and unpublished clinical trials in searches for systematic reviews. In information science the term → document includes museum objects and archival records, but these kinds of documents are in practice seldom (if ever) included in the literature about bibliographic control, although theoretically they might be. Taylor and Winstanley (1990) from the British Library thus suggested a project for bibliographical control of computer files. Bibliographic control is to make it possible to identify the documents of relevance for a given query. KO, cataloging, and document descriptions are tools for providing bibliographical control, but not in themselves bibliographical control. For some domains, it is of utmost importance to ensure bibliographical control, and especially in medicine this is taken very seriously, with much research about the coverage and quality of different databases, as we shall see later in this article. But such control should in principle be equally relevant for all domains.

If one library in the world — whether a physical or a digital library — could have a copy of all documents ever produced, the catalog of that library could be said to provide a kind of universal bibliographical control [5]. The Library of Alexandria, for example, seems to have had this ambition (see Section 2.1 below). There are alternative ways in which universal bibliographical control have been approached. They include attempts making comprehensive universal bibliographies, such as Bibliotheca Universalis (see Section 2.2), the Universal Bibliographical Repertory (see Section 2.4), union catalogs with WorldCat (Section 2.5) and the World Wide Web (WWW) with Google (Section 2.7). A bibliography/bibliographical database makes it possible to identify relevant documents, but often leaves the task of locating those documents to libraries, digital archives or publishers to library catalogs or related tools. An alternative to one comprehensive bibliography is represented by IFLA's and UNESCO's program on universal bibliographical control with the goal to establish a system of national bibliographies which together could provide universal control (Section 2.6). In practice, however, the most useful has been the system of abstract journal and subject bibliographical databases (Section 2.3) although this system is dependent on and varies in coverage and quality from discipline to discipline.

Section 2 describes these projects in chronological order based on their first appearance, but first we consider a suggestion to distinguish between two kinds of bibliographical control.

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1.2 Two kinds of bibliographical control

→ Wilson (1968) made a distinction between two kinds of bibliographical control: (1) “exploitative control”, (2) “descriptive control”.

1. If one is reading for a purpose (and is a rational person) then one would like the best textual means to one's end. Therefore, (ibid., 22) “the more important sort of bibliographical control is this: to have the power to produce the best textual means to one's ends”.
2. The second sort of power and bibliographic control is to be able to provide a list of documents (or bibliographic records) fitting a certain description, that is evaluatively neutral. Wilson's examples (ibid, 22) are: all writings authored by Hobbes, all writings discussing the doctrine of eternal recurrence, all writings containing the word 'fatuity'”.

Wilson (1968, 69) considers that “The Bibliographic Encyclopedia” resembles 1, while “The catalog” resembles 2. Ibid. (150) he considers the exhaustive national or subject bibliography as the typical instruments of descriptive control, whereas the typical means of exploitative control would be “the 'special' library serving a group of scholars accustomed to talk to each other, and staffed by persons approaching the type of bibliographical consultants rather than the bibliographical aid”.

It might be argued, however, that even the second sort of bibliographic control is not evaluatively neutral (at least not always). It is, for example, not always clear who authored a given document. The present author is not familiar about this issue in relation to the works attributed to Hobbes, but if we change the example to writings by Plato, the question “who wrote Plato's works” has a long history and even gave birth to a hermeneutic tradition [6]. Another example is the works attributed to Shakespeare, known as the Shakespeare Authorship Question, discussed by Boyle, Dudley and Hatinguais (2022) which also includes a critique of how Library of Congress deals with this (or these) authorships. In the contemporary environment, we have problems with ghost writers, pseudonyms, and many kinds of guidelines for assigning authorship to document in an ethical way (see Osborne and Holland 2009). Therefore, even attributing author names to documents may sometime involve disagreements among experts and be interpretations and evaluations, and thus not be “evaluatively neutral”. However, the issue sticks even deeper because it has been questioned that any form of description can be neutral. Bateson (1977, 147), for example wrote:

You can never get away from theories of the nature of description whenever, wherever you have descriptions. All descriptions are based on theories of how to make descriptions. You cannot claim to have no epistemology. Those who so claim have nothing but a bad epistemology. And every description is based upon, and contains implicitly, a theory of how to describe. The Cartesian coordinates contain a theory of how to describe, and for many purposes, I believe, it is an inappropriate and dangerous theory.

Wilson (1968, 32) acknowledges that “description” and “evaluating” are not absolute opposites: “[I]nsofar as we can distinguish between evaluating and ('neutrally') describing, some element of each enters into every remark we ever make about anything, that there are no pure cases of evaluation and none of description, but at best a continuum extending indefinitely in both directions, the end points being unreachable”. Still, however, it seems that Wilson's distinction between the two kinds of bibliographical descriptions is problematic, because descriptions in science and scholarship are influenced by theoretical assumptions and are developed to make identifications and selections possible, and the bibliographical descriptions as an ideal should reflect scientific concepts to make the literature retrievable. Consider the following example:

In evidence-based medicine (EBM) the goal is to identify the part of the literature, that best provides evidence for whether a given treatment is better than another (or better than no treatment). This corresponds to Wilson's first kind of bibliographic power: to identify the best textual means to an end — the end here being choosing the optimal medical treatments.
The tradition known as EBM has developed criteria to distinguish between degrees of evidence in the medical literature. For example, evidence from a randomized controlled trial (RCT) is assigned greater weight than evidence from case studies, which again are given greater weight than clinical experience of respected authorities. Therefore, norms of medical writings demands that the kind of evidence claimed in a medical study is described in the published record of the study (e.g., journal article). At the bibliographical level, the kind of evidence is described by the assignment of subject headings to the journal article by the staff of the National Library of Medicine in the MEDLINE database. The description of the study as it appears in MEDLINE therefore reflects Wilson's second kind of bibliographical control. Because these descriptions are not, and cannot be, neutral (see further in Hjørland 2011) Wilson's distinction between two kinds of bibliographical control collapses.

The collapse of Wilson's distinction can also be observed in best match techniques, the ranking of research results used in modern search engines. Here the documents which are predicted of highest relevance to the user are ranked highest and presented first. This ranking is, however, based on what must be characterized as descriptive elements as opposed to appraisals of the documents.

Alternatively, a more common distinction between two kinds of bibliographical control is suggested here (previously suggested in Hjørland 1997, 20):

1. Subject attribution [7] (subject cataloging, traditionally understood as classification and indexing) is the kind of bibliographical control that support users' identification of unknown documents of potential interest to their queries (e.g., find documents about the doctrine of eternal recurrence or find studies about the relevance of psychotherapy for the treatment of ADHD). Subject assignment requires adequate subject knowledge.
2. So-called descriptive cataloging [8] is the kind of bibliographical control that enables users to identify known items of which some characteristics such as author, title, or publisher are known [9]. Such characteristics can be searched in databases and help the user find a record that allows them to get a copy of the document, e.g., from a library or a publisher. Descriptive cataloging is less dependent on subject knowledge, and more dependent of knowledge associated with descriptive bibliography and traditions of document description.

We have now discussed the meaning and the functions of the term bibliographical control and will now turn to prominent historical and contemporary projects for establishing this.

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2. Important historical examples of bibliographical control

This section presents a range of projects from the Library of Alexandria to the Internet, which have in different ways provided comprehensive bibliographical control of books and other kinds of documents. The examples have been chosen from what is by this author considered the most prominent and theoretically important ones in the history of bibliographical control. Each project has fulfilled important goals, and most of them also seems to reveal a dream of an unobtainable goal: to provide complete control of → “information”. This presentation of former projects, the assumptions on which they were based, and the criticism and debate related to them, may hopefully provide a basis for considering future projects. They are described very briefly, and with only a few references and many of them deserve an independent article in this encyclopedia.

2.1 Library of Alexandria (c. 285- BC)

Erskine (1995, 39) wrote about the aims and acquisitions of this library:

It is clear from our evidence, scrappy as it is, that the Ptolemies made a determined effort to obtain as many books as possible for their library. Buying up books in the book markets of Athens and Rhodes was one way of increasing the collection[7] [10] but the Ptolemies also turned to more extreme methods. According to Galen all books found on board ships that docked in Alexandria were seized, taken away, and copied. Then the copies, not the originals, were returned to the owners. The books acquired in this way were marked 'from the ships'. The Athenians, perhaps, should have known better than to lend one of the Ptolemies their precious official edition of the tragedies of Sophocles, Aeschylus, and Euripides, even if he did give them 15 talents as a security. The king kept the originals and returned the copies with the small consolation that they were produced on the very best papyrus available[8]. Whatever the truth of these stories the view prevailed that the Library's appetite for books was voracious. Some even suggested that the Ptolemies wished to acquire copies of all books ever written, though translated into Greek first[9].

To have all written books within the library is an important step towards bibliographical control, but the next step: to make them retrievable, is also important. We have not much knowledge about the degree to which retrievability was obtained. It is obvious, however, that this library deserves a prominent place in the history of bibliographic control. How the books were organized and retrieved in this library has been discussed by Olesen-Bagneux (2014). About the Library of Alexandria see further in El-Abbadi (1990).

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2.2 Gessner's Bibliotheca Universalis (1545)

The Swiss naturalist and bibliographer Conrad Gessner published in 1545 Bibliotheca Universalis, the first bibliography of all known books in Hebrew, Greek and Latin after the invention of printing, in alphabetical order. Followed in 1548 by Pandectae, which was a systematic arrangement of the same bibliographical references. Although incomplete [11], these works made Gessner a pioneer in the field of bibliography (he is sometimes called “the father of bibliography”), and Bibliotheca Universalis one of the main examples in the history of bibliographical control and an inspiration for many later attempts to produce comprehensive bibliographies. See further in Crippa and Araujo (2020) and Fischer (1966).

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2.3 The abstract journal and subject bibliographical databases (1790-)

In the LIS literature about bibliographical control, scholarly bibliographical databases are seldom considered. This is here considered a shortcoming as they probably represent the most important element. The abstract journal understood as a journal providing abstracts of articles in other journals became influential from the 19th century (see Manzer 1977 and Fyfe 2021), and abstract journals soon became a dominant element in scientific communication to establish bibliographical control over the scientific literature in their respective disciplines. In the beginning they were published as printed journals, in a period also as microfilm publications, but from the 1960s also as electronic databases (paper editions typically ceased to be published about 2000).

The electronic databases made a huge difference for scholarly communication and gave rise to the field of information retrieval. The many innovations are described by Bourne and Hahn (2003). Another dimension of this revolution was the emergence of → citation indexes (see Araújo, Castanha and Hjørland 2021).

The development of the citation indexes provides an important new, if not revolutionary perspective on bibliographic control: the idea that documents are linked in networks by their citations, and that the authors of these documents — prominent subject specialists — produce a kind on self-organizing system, which provides a kind of bibliographic control (as all scientific papers are supposed to be based on the most important knowledge/documents, this must be reflected in their bibliographical references). Seen in this perspective we have two competing systems of bibliographical control: one made by bibliographic databases, and one made by the primary literature itself. These two systems supplement each other (with surprisingly little overlap), and their relative effectiveness is an important topic for research (see Pao and Worthen 1989; Pao 1993a; Pao 1993b; Hjørland and Kyllesbech Nielsen 2001, 272-77; Hjørland 2013 and Hirt et al. 2022).

The system of separate subject bibliographies as an approach to bibliographic control may, in contrast to some alternatives, be considered what Taube (1951, 67) described as “separate, overlapping, duplicating bibliographical services — a chaos of conflicting organizations and purposes from which current national bibliography and current complete universal bibliography […] were to rescue us?”. But after a careful analysis of the issues involved, he found that systems for special disciplines after all is the best alternative because “the categories of any discipline will reflect the basic interests and the purposes of those concerned with that discipline” (p. 71). It should be added that Taube's analysis was explicitly based on a “functional approach”.

The revolution that started with scientific bibliographic databases continues today with Internet technologies (see Section 2.7) but databases focusing on scholarly communication should still be considered an extremely important element of bibliographic control over the information ecosystem (and not just something that is made obsolete by the WWW).

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2.4. Universal Bibliographical Repertory (RBU) (1895-)

The Universal Bibliographical Repertory (Répertoire bibliographique universel, RBU) or “the universal bibliography” was described by Paul Otlet [1897] as “an inventory of all that has been written at all times, in all languages, and on all subjects” (here cited in translation after Wright 2014, 76). It is the best known among other attempts to provide bibliographical control about the fin de siècle. A rival to RUB was the London-based International Catalog of Scientific Literature (see Csiszar 2013).

RUB was produced by the International Institute of Bibliography (Institut international de bibliographie, IIB). By 1934 nearly 16 million cataloging cards had been collected and classified in the RBU. In the beginning it was classified according to the Dewey Decimal Classification (DDC), but the very large extent of the bibliography made it necessary to develop a new system: the Universal Decimal Classification (UDC).

The Repertory received requests from all over the world and answers send by mail in the form of copied cards relevant to the query, and Otlet was very much interested in applying new technologies. Unfortunately, the project lost its financial basis and much of the repertory was lost. It is a question, however, if the project could and should have continued, or if a system of subject bibliographies (see Section 2.3) or of national bibliographies (see Section 2.6) would be better strategies. Wright (2014, 72) referred some contemporary objections and criticism of it: “Some objected to the project on its most basic premise, arguing that true universality across disciplines was an unachievable dream; better to have subject-specific schemes tailored to the nuances of each discipline rather than one shallow classification that tried to cover every subject under the sun”.

RUB has been called a paper forerunner for Google and is today a part of the Mundaneum museum supported by Google [12]. Csiszar (2013, 443; italics in original) wrote, however:

[I]t is not obvious that the best way to deal with the literature problem should have been grandiose subject classification projects. Other more traditional — some might say more sensible — options existed: better specialized disciplinary bibliographies, expanded alphabetical subject indexes, or even relying more on the accumulated knowledge of recognized experts. (Indeed, given the ultimate failure of many of these projects, it might plausibly be argued that in hindsight universal and detailed classification was a misguided approach.)

See further in Otlet (1990), Heuvel (2009) and Wright (2014).

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2.5 Union catalogs (1930s-)

Union catalogs are catalogs which list the holdings in more than one library or collection. They may be book catalogs, journal catalogs, incunabula catalogs etc., they may be national or international, universal or subject-specific etc. Although the earliest union catalogs go back to the 12th and 13th century, they have reached a much larger size in the 20th century, in both print and electronic forms. The electronic WorldCat database is described below. Here we shall only mention one example of printed union catalogs: the National Union Catalog, Pre-1956 Imprints, which is a 754-volume set containing books catalogued by the Library of Congress and other American and Canadian libraries in alphabetical order. This printed mammoth represents the apogee of printed catalogs and bibliographies which lost their relevance in the online era. See further in Creider (2010) and Lass and Quandt (2004).

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2.5.1 WorldCat (1971)

WorldCat is a union catalog database provided by OCLC (formerly known as Online Computer Library Center), which is an American nonprofit cooperative organization. It is the largest database of its kind, and was established in 1971, but only got its present domain name in 1998. White and Zuccala (2018, 1502) wrote:

WorldCat lists the holdings of more than 16,000 members; public, academic, and research libraries are major types. These libraries are mainly in North America, but they extend around the globe. Books in English dominate their collections, but many also have sizable holdings in other languages.

Compared to the subject bibliographical databases (see Section 2.3), union catalogs, including WorldCat, do not provide the same degree of bibliographic control, especially on article indexing. They serve, however, other functions, in particular (1) known-item verification of monographs and (2) locating of monographs in libraries. See further in Fowler (2010, 1269).

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2.6 IFLA's and UNESCO's program on universal bibliographic control (1970s-)

The International Federation of Library Associations and Institutions (IFLA) and the United Nations Educational, Scientific and Cultural Organization (UNESCO) had in the 1970s a program on “universal bibliographic control” which was based on the idea that each nation should produce a national bibliography, and that international cooperation among national bibliographies should ensure “universal” bibliographic control. IFLA Professional Statement on Universal Bibliographic Control (2012) wrote:

A National bibliographic agency (NBA) has the responsibility for providing the authoritative bibliographic data for publications of its own country and for making that data available to other NBAs, libraries, and other communities (for instance archives and museums) through appropriate and timely services with the goal of increasing open access to the bibliographic data.

National bibliographies themselves are much older than IFLA's program (although the present meaning of “national bibliography” only goes back to the 1950s) [13]. For example, Dansk bogfortegnelse (Danish national bibliography: Books) has been published since 1851. Their preparation is often made by (and dependent of) national libraries and the concept of legal deposit of publications. The first law on legal deposit is from France in 1537 under which a copy of any published book had to be delivered to the king's library, for conservation purposes, and sometimes to facilitate censorship. Similar laws were passed in many other European countries. By contrast, in the U.S.A. the delivery of copies of printed books to the Library of Congress serve copyright purposes. This makes a difference of what books come under bibliographic control and exemplify how different interests influences the contents of national bibliographies.

It is a common misunderstanding, perhaps a kind of hype, that national bibliographies represent a prerequisite for all other bibliographies, and thereby have a foundational role in bibliographic control. This view was expressed by Downs (1954, 500):

Viewing the question of bibliographical control in the perspective of history, there seems little doubt that effective national bibliographic organization must precede international or universal coverage. Starry-eyed bibliographers, who for generations have advocated a worldwide approach to bibliography, present an almost unbroken record of futility, frustration, and failure, except, perhaps, when they limit themselves to special aspects. If universal bibliography is ever to be achieved, it must be grounded upon the work of individual countries. [14]

This view was also expressed by Chaplin (1975), who found that a necessary foundation of library and information services is knowledge of what documentary material exists. And (p. 48):

Providers of specialized information naturally rely largely on specialized sources: abstracting services, journals and bibliographies relating to the disciplines in which their own major interests lie. But these sources must themselves select their material from wider, less-specialized sources.

Therefore he found that “a future integrated bibliographic and information system might be based on two interrelated categories of records—national records of separate publications, unrestricted in subject-matter, and international records of contributions to knowledge (whether separate publications or not), limited to particular subject fields”.

However, scientific bibliographical databases such as MEDLINE, Web of Science, Scopus, PsycINFO etc. simply do not have their input from national bibliographies, and Taube (1951) argued that to base subject bibliographies on the representations of universal bibliographies and catalogs is also theoretically a bad idea because different contexts need different subject headings. Taube (ibid., 66-67) exemplified his argument that the Library of Congress Subject Headings were too general to be used by the Department of Agriculture or by the Army Medical Library. And the other way round: the subject headings of a special library are too specific to be used by the Library of Congress. He wrote (67):

But when the Library of Congress rejects a heading supplied by a special library, it prints the rejected heading along with its own heading because the Library of Congress officially recognizes that the purpose of a special library may require a degree of specificity in indexing not necessary or desirable for its own general purposes. In short, the distinction we discerned between general and special classification systems also exists between general and special collections of subject headings. And we conclude that there cannot be one subject key to bibliographic organization which would serve the librarian, the general reader, and all specialists.

IFLA's program focused mostly on cataloging standards (and this may be the reason for the widespread confusion of bibliographical control with KO and document description mentioned in Section 1). Critical attitudes have been expressed in relation to library cataloging, and by implication to this way of providing bibliographical control. Line (2005, 110-111) is one example of this criticism. He wrote:

AACR2 [Anglo American Cataloging Rules 2nd ed.] is one of the most remarkable examples of trying to solve a problem by committee, with predictable results. The committee did not even tackle the right problem — what users surely want is not comprehensive or perfectly accurate bibliographic records, but far better subject access to books, comparable with that provided for scientific journal articles by the large international databases. No data on users' needs, whether for bibliographic information or subject access, were collected; instead, cataloguers discussed how to change the rules, rather as if hens were to gather together to discuss the design of eggs. I am however doing the committee an injustice in accusing them of not involving consumers in their discussions, because much of the use made of catalogues is in fact by cataloguers for the purpose of adding to them. Cataloguers would lose their status if it were shown that most cataloguing is a trivial job easily done by clerical staff or that the length of a catalogue entry was not a sign of virility.

Dunsire, Hillmann and Phipps (2012) suggested that bibliographic control in general, including the IFLA program, should consider the technologies of semantic Web and linked data to provide better utilization of the metadata produced by many different groups and organizations. The discussion of these technologies cannot be done in the present article and is more an issue about document representation than about genuine bibliographic control. However, the article's argument (p. 164) to replace attempts based on “one-size-fits-all schema, rules and other international/global standards with what might be termed an all-sizes fit-one approach [… which] can support a much richer ecology of bibliographic communities and their standards” seems to be an important idea.

The IFLA program is further described in Anderson (1974; 1984).

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2.7 The World Wide Web (1989-) and Google

WWW is a → hypertext information network proposed in 1989 by Tim Berners-Lee and Robert Cailliau at the European Organization for Nuclear Research (CERN), in 1990 termed “World Wide Web”, and launched by CERN on May 17, 1991. That system quickly revolutionized almost everything in the world. Its strength is the broad possibility of cooperating, that anybody with a computer can both draw from and contribute to the network of information resources, which set free a huge amount of labor. For example, Wikipedia was launched in 2001, stunned the world, and made times hard for established encyclopedias such as Encyclopaedia Britannica.

Google Search (also known as Google) was originally developed in 1996 by Larry Page, Sergey Brin, and Scott Hassan. It is a search engine designed to retrieve documents offered by web servers (WWW). It can find text, images and other media and provide access to free documents or to paywalls, where documents can be retrieved by payment. Of course, not all the information in the world is on the WWW, and there is information on the WWW that Google and other search engines do not reach (the so-called deep Web, see Zheng et al. 2013 and dark Web, see Sobhan et al. 2022).

Google [2019] wrote about itself: ”Our mission is to organize the world's information and make it universally accessible and useful”. Google has achieved, among other things:

1. To make the search engine with most comprehensive coverage of webpages (often including published full-text documents).
2. Google Scholar, a database with a citation index and an impressive coverage of scientific literature. (According to Gehanno, Rollin, and Darmoni (2013) it contains more relevant medical studies than MEDLINE (of 738 original studies included in a gold standard database all were found in Google Scholar, which is extraordinary). As stated later, even if this should be the case, MEDLINE may still provide better retrieval in subject searches.)
3. Google Books has made many million books available on the Internet, full-text searchable. Many as free books, but many only with limited reading possibilities. In many cases, it provides facilities to locate, for example, quotations, much better than the printed index in the books themselves.

In one way, Google represents the closest the world has ever come to universal bibliographic control. On the other hand, it could be said that Google does not really represent bibliographic control because links and documents often disappear (and the control thereby disappears). This is a problem that → web archives such as the Internet Archive try to tackle. Apart from coverage, the issue is retrievability in subject searches. At this point classical bibliographical databases seem to perform better compared to Google's full-text search possibilities, due to better indexing and metadata. This problem is probably the most important one in information science today.

See further about the history of the Web and the Web in general in Gillies and Cailliau (2000); Gardiner and Musto (2010); Tomer (2017). About coverage and retrieval effectiveness of Google see Lewandowski (2008); Gehanno, Rollin and Darmoni (2013); Bramer, Giustini and Kramer (2016); Gusenbauer and Haddaway (2020); Hjørland (2021).

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3. Theoretical problems in obtaining bibliographical control

It is obvious that the goal of obtaining comprehensive coverage in bibliographical databases meets many practical and financial problems. The cost of labor (and/or computer resources) to carry out the identification and describing of documents has always been an obstacle. The idea to make a bibliography is relatively simple but requires much work to fulfill. However, such practical issues cannot be addressed in information science and knowledge organization where the focus must be on the theoretical problems, including how to evaluate the effectiveness of different solutions. Two main theoretical issues concerns (1) coverage and (2) retrievability from the contents of a given database.

Concerning (1) coverage, the first issue to consider is that despite the impression of completeness, any bibliographical database is always selective. The medical database MEDLINE, for example, contains more than 29 million references to the biomedical literature. Why isn't that enough? Experiences from systematic reviews show that more than this database is needed if a satisfactory identification of relevant findings should be obtained [15]. The problem lies in the selection of journals (or in general: information resources). Any selection must be based on criteria, and any set of criteria are only indicators, not a waterproof guarantee that all relevant items are included. Bradford (1953, 148) wrote about the scattering of articles on a given subject:

It is, therefore, necessary to examine the extent to which articles on a given subject actually occur in periodicals devoted to quite other subjects: as, for instance, a paper on the mechanism of the heart, contributed to the Proceedings of Physical Society, or one on genetics, occurring in an agricultural magazine. Investigation shows that this distribution follows a certain law, which can be deduced both theoretically from the principle of the unity of science and practically from examination of the references.
According to this principle every scientific subject is related, more or less remotely, to every other scientific subject.
It follows that from time to time, a periodical devoted to a special subject may contain an article of interest from the point of view of another subject. In other words, the articles of interest to a specialist must occur not only in the periodicals specializing on his subject, but also, from time to time, in other periodicals, which grow in number as the relation of their fields to that of his subject lessens and the number of articles on his subject in each periodical diminishes.

This means, according to Bradford, that no subject database can ever be expected to have full bibliographical control. This problem is not relevant for universal databases such as Google Scholar (and less important in Web of Science, which is more selective), but still, complete coverage is an unobtainable dream. Following this principle, journals may be classified into “zones”, where zone 1 represents the journals that have most articles on the subject, zone 2 includes the journals that have had an average amount of articles, and zone 3 comprises the long tail of journals that occasionally or seldom contain articles about that subject. Such classifications have been used as selection criteria for special libraries and databases, but this implicitly acknowledges the impossibility of full theoretical coverage. There is, however, a perspective, that was neglected by Bradford, and has only been understood recently: Bradford realized that all documents are related to all others (due to the doctrine of unity of science). But how should we decide which are most closely related — and therefore important to include in a subject bibliography? The answer to this question is theory-dependent and may shift with “paradigm-shifts” in a field, and thus on interpretations rather than simple statistical figures about word frequencies or related data. This is again an example of the difference between “positivist” and “pragmatist” philosophy.

Although Google has an extremely comprehensive index of the Internet, not all pages are updated with the same frequency, and there are still problems like the dark Web, although, as said in Section 2.7, Gehanno, Rollin, and Darmoni (2013) found that Google Scholar has a better coverage than MEDLINE. More studies are needed to determine the relative coverage of the relevant literature, because other studies have indicated otherwise [16], because the databases seem to be competing and due to constant development. It is important to realize, that it is studies of this kind that really provide important information about whether bibliographical control is satisfactory or not.

Concerning (2) retrieval from the contents covered by a given database, to have the relevant documents in a database (or in an Internet index like Google's) represented in a database is one thing. How to select the document for a given query from this database/index is another. This problem is the subject of the whole field of information retrieval, and numerous approaches have been suggested and tried, which will not be presented in this article. Swanson (1986) expressed a problem, that sadly has been neglected in the literature of information science. He wrote:

The search process, like a scientific theory, can be criticized and improved, but can never be verified as capable of retrieving all information relevant to a problem or theory. This essential incompleteness of search and retrieval therefore makes possible, and plausible, the existence of undiscovered public knowledge.

This is also a problem for both MEDLINE and Google (and Google Scholar). MEDLINE relies on Medical Subject Headings (MeSH) the effectiveness of which seems to be taken for granted by the National Library of Medicine but seems to need further research. About search engines like Google, it has frequently been pointed out in the research literature that they are not neutral, objective machines (Introna and Nissenbaum 2000; Granka 2010). Therefore, Lewandowski (2014) found that there is a need for alternatives, for many competing search engines. The problem of obtaining this is the extremely costly process of establishing a basic index of the Web on which the competing search engines could operate. About this, he wrote (p. 57):

This type of project will require a considerable investment of funds. The total cost cannot be precisely forecast here. Several hundred million euros will likely be needed, however, when one considers the anecdotal reports provided by search engine operators. The losses Bing has reported on its search activities are one example. This may appear prohibitively expensive until one considers, for instance, that the German government invested roughly 100 million euros in the semantic technology developed as part of the Theseus program. Nevertheless, it is still clear that any one country alone cannot support this type of project. The only feasible option is a pan-European initiative.

Because of these issues, as stated in Section 1, bibliographical control in an absolute meaning is an unobtainable goal, even in principle. As pointed out by Wright (2014) all such ambitions throughout history represent a problematic positivist view — not the least Google's aim “to organize the world's information and make it universally accessible and useful”. (For a criticism of the principles on which Google is based, see Hjørland 2021.) Wright's theoretical analysis and critiques of approaches to bibliographical control are valuable, although one misses an analysis of what the opposite to positivism is, and how such an alternative would approach the issue of bibliographical control. The opinion of the present author is that this question holds the key to solving the fundamental problems of information science. In the present article the approach represented by scientific bibliographical databases comes closer to non-positivism (by avoiding universalist ideas), although also at this next level, these opposite philosophies are at play in the way they select and represent documents.

But that does not mean that these efforts (including Google's) have not been extremely useful. What it means is that research needs to be based on a better theoretical and philosophical basis, and that further progress should be based on developing information systems optimal for specific purposes, interests, and disciplines rather than on mistaken philosophies [17].

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4. Conclusion

The idea of bibliographic control from the Library of Alexandria to the present date is an exciting story that demonstrates how different ages have used their available technologies and ideas to achieve the goal associated with this idea. The idea has often been associated with positivist dreams of universal, complete, all-purpose, and value-free collections, bibliographies, and retrieval systems. It is also often associated with the view that this goal will be provided by advances in information technology rather than by advances in the understanding of the goals to be fulfilled. An important exception from this common view is Wilson (1968), who wrote (p. 5):

There is less of conceptual innovations [in relation to bibliographical control] in most remedial proposals than enthusiasts and promoters think, but the impressive technology is undeniable. But technology tells us neither what is worth aiming at (or away from), nor what is satisfactory degree of progress toward our elected goals. That we must discover or decide for ourselves; and that is best done with the greatest possible clarity about alternative goals and the intrinsic difficulties in their pursuit.

Among the suggestions found in the literature on bibliographical control are some important ideas, including (1) to consider the network of citing papers a kind of self-organizing system for bibliographic control competing with bibliographies established by others, (2) the establishing of a public index of the Internet (Lewandowski 2014) on which competing search engines can be built to better meet different goals and interests and (3) an idea, that is not new but now suggested for the new Internet technologies, is the claim by Dunsire, Hillmann and Phipps (2012) that bibliographical control must be adjusted to the needs of different purposes, groups, and subject. The present author finds that this last view also was the main message in Wilson (1968).

At the most general level, the conclusion in relation to bibliographical control is the same as for all other issues in information science and KO: there are no pure technological, neutral, solutions, and ambitions to make all information in the world available for all purposes and interest is ill-conceived. At the philosophical level, the field should turn from (implicit) positivist assumptions to explicit functional/pragmatic research strategies.

The problem of bibliographical control is important, but seems to be neglected, or redefined to be about document descriptions. This article has used some examples from the medical domain to illustrate how the goal to establish bibliographical control is important and addressed by research about the coverage of databases and the retrievability of documents in the various databases. Hopefully, similar attention will develop in other domains, and come more in focus in information science with KO.

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