Y. Song, L. Zhang, and C. Giles. CIKM '08: Proceeding of the 17th ACM conference on Information and knowledge mining, page 93--102. New York, NY, USA, ACM, (2008)
C. Basu, H. Hirsh, and W. Cohen. AAAI '98/IAAI '98: Proceedings of the fifteenth national/tenth conference on Artificial intelligence/Innovative applications of artificial intelligence, page 714--720. Menlo Park, CA, USA, American Association for Artificial Intelligence, (1998)