BRITISH LIBRARY (UK)
To identify/locate various documents in Europe's largest lending library!
NATIONAL LIBRARY OF MEDICINE (EUA)
To identify/locate various documents in the largest medical library in the world!
PORBASE [BIBLIOTECA NACIONAL - PORTUGAL]
As a result of the cooperation of several libraries, it allows you to locate/identify books and various kinds of monographs (e.g. theses) in Portuguese libraries.
EUROPEANA
A multilingual collection of millions of digitized items from libraries, museums, archives, and collections as a result of policies to preserve and provide access to cultural heritage within the European Union.