P. Melville, R. Mooney, and R. Nagarajan. Eighteenth National Conference on Artificial Intelligence, page 187--192. Menlo Park, CA, USA, American Association for Artificial Intelligence, (2002)
A. Popescul, L. Ungar, D. Pennock, and S. Lawrence. Proceedings of the 17th Conference on Uncertainty in Artificial Intelligence, page 437--444. San Francisco, CA, USA, Morgan Kaufmann Publishers Inc., (August 2001)