B. Sarwar, G. Karypis, J. Konstan, and J. Riedl. Proceedings of the 2nd ACM Conference on Electronic Commerce, page 158--167. New York, NY, USA, ACM, (2000)
T. Joachims, L. Granka, B. Pan, H. Hembrooke, and G. Gay. Proceedings of the 28th Annual International Conference on Research and Development in Information Retrieval, page 154--161. New York, NY, USA, ACM, (2005)
I. Niemelä, P. Simons, and T. Soininen. Proceedings of the 5th International Conference on Logic Programming and Nonmonotonic Reasoning, page 317--331. London, UK, Springer-Verlag, (1999)
M. Stumpner, A. Haselbock, and G. Friedrich. Proceedings of the 10th Conference on Artificial Intelligence for Applications, page 373-380. San Antonia, TX, USA, (1994)