ABSTRACT
In order to reduce the problems of information overload, librarians and indexers have created systems of categorization that allow large numbers of individual books or articles to be perceived initially through smaller numbers of categories of literature. These categories can be either subject or format groupings. Format designations are particularly useful in segregating reference works from larger collections or retrievals. The distinctive nature, and the purposes and uses of reference works (“tertiary literature” composed of 60% or more of files or lists, as opposed to “primary” or “secondary” literature) are discussed. The mechanisms for finding such works via Library of Congress Subject Headings, or via the peculiarities of their shelving in either the Library of Congress Classification or the Dewey Decimal Classification, are explained. “Publication types” and “document type” searches within databases covering formats other than books are also treated.
