R. Yan, C. Huang, J. Tang, Y. Zhang, and X. Li. Proceedings of the 12th ACM/IEEE-CS joint conference on Digital Libraries, page 51--60. New York, NY, USA, ACM, (2012)
P. Heymann, D. Ramage, and H. Garcia-Molina. SIGIR '08: Proceedings of the 31st Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, page 531--538. New York, NY, USA, ACM, (2008)