Library Catalogs on the Web
- Library of Congress Online Catalog
- The de facto national library of the United States and the research arm of the United States Congress.
- The European Library
- Portal which offers offers the ability to search the Union Catalog of Europe’s National Libraries.
- The Karlsruhe Virtual Catalog KVK
- A meta search interface which allows access to library and book trade catalogs via WWW.
- Western European Library Catalogs
- Union catalogs and groupings arranged by country.
- WorldCat Advanced Search
- Search interface of a cooperative database of bibliographic records.