"WorldCat is an online union catalog of materials held by OCLC member libraries. OCLC, Online Computer Library Center, is a nonprofit, membership, library computer service and research organization. WorldCat contains millions of bibliographic records describing items owned by libraries around the world. Item records provide information about individual library holdings. Types of materials include books, journals, musical scores, computer data files, magazines, newspapers, computer programs, sound recordings, films and slides, maps, videotapes, and manuscripts written as early as the 12th century. Updated daily."