The Classical Works Knowledge Base (CWKB) is a new service of the American Philological Association developed under the direction of Eric Rebillard (Cornell University). The project was supported by a grant made to the American Philological Association (APA) in 2010 by the Andrew W. Mellon Foundation.
CWKB contain information for the retrieval of citations from ancient Greek and Latin texts--from Homer (8 c. BC) to Bede (mid 8 c. AD)-- in the following online resources: Brepols Library of Latin Texts, Perseus Library, PHI Latin Texts, Thesaurus Linguae Graecae.
CWKB adopts an OpenURL approach. It is both a relational database and a link resolver software. The relational database stores metadata about authors and works; the link resolver parses the OpenURLs, makes a lookup in the relational database, and returns links to digital libraries of Greek and Latin literatures. This web page has more information.
L'Année philologique online is the first resource to use CWKB for linking citations of ancient texts to digital libraries of text.