T. Chiu, D. Fang, J. Chen, Y. Wang, and C. Jeris. KDD '01: Proceedings of the seventh ACM SIGKDD international conference on Knowledge discovery and data mining, page 263--268. New York, NY, USA, ACM, (2001)
A. Anjewierden, W. Chen, A. Wichmann, and S. van Borkulo. Proceedings of the 8th International Conference on Computer Supported Collaborative Learning (CSCL 2009), Rhodes, Greece, (June 2009)
B. Yang, J. Sun, T. Wang, and Z. Chen. KDD '09: Proceedings of the 15th ACM SIGKDD international conference on Knowledge discovery and data mining, page 917--926. New York, NY, USA, ACM, (2009)
J. Tang, H. fung Leung, Q. Luo, D. Chen, and J. Gong. Proceedings of the Twenty-First International Joint Conference on Artificial Intelligence, page 2089-2094. Pasadena, California, USA, (2009)