OCLC WorldCat.

"WordCat is world's largest network of library content and services....WorldCat.org lets you search the collections of libraries in your community and thousands more around the world. WorldCat grows every day thanks to the efforts of librarians and other information professionals."

WorldCat is a service of OCLC which originated in 1967. "As of March 2015, the OCLC database contained over 336M records with 2.2 billion cataloged items, and is the world's largest bibliographic database covering 72,000 libraries."^[24] http://www.worldcat.org/