Additional information may support particular database functions such as search, or browse (e.g., by keywords), or may provide fuller presentation of the content item (e.g., the article's abstract).
[2] Bibliographic records can represent a wide variety of published contents, including traditional paper, digitized, or born-digital publications.
The earliest known bibliographic records come from the catalogues (written in cuneiform script on clay tablets) of religious texts from 2000 B.C., that were identified by what appear to be key words in Sumerian.
[4] Early American library catalogs in the colonial period were typically made available in book form, either manuscript or printed.
[7] The subject bibliography databases (such as Chemical Abstracts, Medline, PsycInfo, or Web of Science) do not use the same kinds of bibliographical standards as does the library community.