Grigory Begelman, Philipp Keller, Frank Smadja; Technion Israel Institute of Technology, Citrin Informatik GmbH and RawSugar at Collaborative Tagging Workshop WWW 2006
Baader: Description logics as ontology languages for the semantic web. in Hutter et al. (Hrsg.): Mechanizing Mathematical Reasoning: Essays in Honor of Jörg Siekmann on the Occasion of His 60th Birthday, LNAI 2605, S. 228-248. Springer, 2005.
C. Cunha, A. Bestavros, and M. Crovella. BU-CS-95-010. Computer Science Department, Boston University, 111 Cummington St, Boston, MA 02215, (July 1995)