J. Koren, Y. Zhang, and X. Liu. WWW '08: Proceeding of the 17th international conference on World Wide Web, page 477--486. New York, NY, USA, ACM, (2008)
Y. Koren. KDD '08: Proceeding of the 14th ACM SIGKDD international conference on Knowledge discovery and data mining, page 426--434. New York, NY, USA, ACM, (2008)