Worldcat
This is the world's most comprehensive bibliography, containing over 179 million records; it includes holdings information from most of the world's libraries. Information is included on books, manuscripts, websites and internet resources, maps, computer programs, musical scores, films and slides, newspapers, journals and magazines, sound recordings, journal articles, book chapters, papers, and videotapes. Although it is primarily a citation database, many records include abstracts, summaries, tables of contents, and brief reviews.