Y. Xu, K. Wang, B. Zhang, and Z. Chen. WWW '07: Proceedings of the 16th international conference on World Wide Web, page 591--600. New York, NY, USA, ACM, (2007)
Y. Xu, K. Wang, B. Zhang, and Z. Chen. WWW '07: Proceedings of the 16th international conference on World Wide Web, page 591--600. New York, NY, USA, ACM Press, (2007)