Y. Song, Z. Zhuang, H. Li, Q. Zhao, J. Li, W. Lee, и C. Giles. Proceedings of the 31st Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, стр. 515--522. New York, NY, USA, ACM, (2008)
T. Joachims. Proceedings of the 12th ACM SIGKDD international conference on Knowledge discovery and data mining, стр. 217--226. New York, NY, USA, ACM, (2006)