D. Shen, Z. Chen, Q. Yang, H. Zeng, B. Zhang, Y. Lu, und W. Ma. Proceedings of the 27th annual international ACM SIGIR conference on Research and development in information retrieval, Seite 242--249. New York, NY, USA, ACM, (2004)
C. Ullrich, J. Wang, R. Shen, und F. Quosdorf. International Conference on Artificial Intelligence and Computational Intelligence, 4, Seite 510--514. Los Alamitos, CA, USA, IEEE Computer Society, (2009)