Y. Sure, S. Bloehdorn, P. Haase, J. Hartmann, and D. Oberle. Progress in Artificial Intelligence --- Proceedings of the 12th Portuguese Conference on Artificial Intelligence (EPIA 2005), December 5-8, 2005, Covilhã, Portugal, volume 3803 of Lecture Notes in Computer Science, page 218--231. Springer, Berlin--Heidelberg, Germany, (December 2005)
T. Dietterich, A. Ashenfelter, and Y. Bulatov. ICML '04: Proceedings of the twenty-first international conference on Machine learning, page 28. New York, NY, USA, ACM Press, (2004)
J. Lafferty, A. McCallum, and F. Pereira. Proc. 18th International Conf. on Machine Learning, page 282--289. Morgan Kaufmann, San Francisco, CA, (2001)
B. Gutmann, and K. Kersting. Proceedings of the 15th European Conference on Machine Learning (ECML-2006), volume 4212 of LNAI (Lecture Notes in Artificial Intelligence), page 174--185. Berlin, Germany, Springer, (September 2006)