Canonical Text Services
The project also has a Sourceforge site, with more recent information: http://cts3.sourceforge.net/
There is a mailing list, too: https://lists.sourceforge.net/lists/listinfo/cts3-general
The Canonical (previously 'Classical') Text Services specification defines a network service for identifying texts and retrieving fragments of texts using notions of "work" and "citation" traditional in classical studies and other literary disciplines.
A CiteULike CTS bibliography by Alison Babeu.