D. Embley, D. Campbell, R. Smith, and S. Liddle. Proceedings of the 7th International Conference on Information and Knowledge Management, page 52 - 59. Bethesda, MD, (1998)
A. McCallum, and W. Li. Proceedings of the seventh conference on Natural language learning at HLT-NAACL 2003, page 188--191. Morristown, NJ, USA, Association for Computational Linguistics, (2003)
M. Pasca, D. Lin, J. Bigham, A. Lifchits, and A. Jain. Proceedings of the 21st International Conference on Computational Linguistics and 44th Annual Meeting of the ACL, page 809--816. Sydney, Australia, (2006)