Special Section: 50 Years of Citation Indexing

EUGENE Garfield’s seminal paper ‘Citation indexes for science’ and his subsequent response to Schoenbach provided the intellectual foundation for the wide variety of citation indexing products emerging as competitors to what has become the Web of Science (WoS). As Garfield succinctly pointed out, subject or classified indexes can, as a practical matter, only provide ‘subject’ access at the article level. Citation indexing, however, takes advantage of an author’s indexing of parts of the article and has the potential to obviate many of the problems scientists experience with indexing terminology and nomenclature. Furthermore, Garfield suggests that, ‘it is impossible for any one person (e.g. the indexer) to anticipate all the thought processes of a user’ ... and ‘by using authors’ references in compiling the citation index, we are in reality utilizing an army of indexers, for every time an author makes a reference he is in effect indexing that work from his point of view’. In this regard, Garfield also alluded to an often overlooked analogy between subject and citation indexing and Chemical Abstracts and Beilstein. Subject indexes, including the Chemical Abstracts General Subject Index (CA GSI), generally index articles at the level at which they are written. For example, a comprehensive review article on ‘Dissociation constants and limiting conductances of organic acids in water’ only has index terms for ‘dissociation constants’ and ‘acids, properties’. While, as Garfield noted, ‘in a certain sense a citation index is not very different from a compendium like Beilstein’ which would index each compound described in the article and relate them to the physical property reported. Fortunately, Garfield’s seminal article ‘Citation indexes for science’ not only led to the Science Citation Index and the WoS, but also to the development of subject retrieval, based on cited references, in a plethora of other services. In contrast with these other services, however, the WoS uniquely offers ‘author/source’ citation searching which, with some diligence, also uniquely retrieves mis-cited or in-press references. Services currently offering cited reference searching include: