C. Körner, R. Kern, H. Grahsl, and M. Strohmaier. Proceedings of the 21st ACM Conference on Hypertext and Hypermedia, page 157--166. New York, NY, USA, ACM, (2010)
D. Parra, and P. Brusilovsky. Proceedings of the Workshop on Web 3.0: Merging Semantic Web and Social Web, volume 467 of CEUR Workshop Proceedings, (June 2009)