Czech Republic - CASLIN - collective catalogue of Czech libraries
Germany - KVK - Karlsruhe Virtual Katalog - searchable collections (books and journals) of German and other foreign libraries
Slovakia - KIS3G - portal of the Slovak library and information system, includes links to library catalogues
United States - The Library of Congress - Catalogues of the Library of Congress
United States - California Digital Library - collections of the University of California libraries and other major research libraries
United Kingdom - JISC Library Hub Discover - English university libraries
United Kingdom - British Library - Catalogue of the British National Library
Other libraries -The European Library - a multi-search engine providing unified access to the electronic resources of Europe's national libraries and library services.