Y. Wang, H. Song, W. Wang, and M. An. PIKM '08: Proceeding of the 2nd PhD workshop on Information and knowledge management, page 57--64. New York, NY, USA, ACM, (2008)
J. Leskovec, L. Backstrom, R. Kumar, and A. Tomkins. KDD '08: Proceeding of the 14th ACM SIGKDD international conference on Knowledge discovery and data mining, page 462--470. New York, NY, USA, ACM, (2008)