H. Zeng, Q. He, Z. Chen, W. Ma, and J. Ma. Proceedings of the 27th annual international conference on Research and development in information retrieval, page 210--217. Sheffield, United Kingdom, ACM Press, (2004)
D. Fetterly, M. Manasse, and M. Najork. SIGIR '05: Proceedings of the 28th annual international ACM SIGIR conference on Research and development in information retrieval, page 170--177. New York, NY, USA, ACM Press, (2005)
G. Jeh, and J. Widom. KDD '02: Proceedings of the eighth ACM SIGKDD international conference on Knowledge discovery and data mining, page 538--543. New York, NY, USA, ACM, (2002)