R. Li, S. Bao, Y. Yu, B. Fei, and Z. Su. WWW '07: Proceedings of the 16th international conference on World Wide Web, page 943--952. New York, NY, USA, ACM, (2007)
M. Magableh, A. Cau, H. Zedan, and M. Ward. Proceedings of the IADIS International Conferences Collaborative Technologies 2010 and Web Based Communities 2010, page 178--182. (July 2010)