A. Agarwal, S. Chakrabarti, and S. Aggarwal. KDD '06: Proceedings of the 12th ACM SIGKDD international conference on Knowledge discovery and data mining, page 14--23. New York, NY, USA, ACM Press, (2006)
J. Zhang, M. Ackerman, and L. Adamic. WWW '07: Proceedings of the 16th international conference on World Wide Web, page 221--230. New York, NY, USA, ACM, (2007)
A. Ukkonen, C. Castillo, D. Donato, and A. Gionis. CIKM '08: Proceeding of the 17th ACM conference on Information and knowledge mining, page 1351--1352. New York, NY, USA, ACM, (2008)
B. Zhang, H. Li, Y. Liu, L. Ji, W. Xi, W. Fan, Z. Chen, and W. Ma. SIGIR '05: Proceedings of the 28th annual international ACM SIGIR conference on Research and development in information retrieval, page 504--511. New York, NY, USA, ACM, (2005)