R. Bekkerman, R. El-Yaniv, und A. McCallum. ICML '05: Proceedings of the 22nd international conference on Machine learning, Seite 41--48. New York, NY, USA, ACM Press, (2005)
L. Baker, und A. McCallum. Proceedings of SIGIR-98, 21st ACM International Conference on Research and Development in Information Retrieval, Seite 96--103. Melbourne, AU, ACM Press, New York, US, (1998)