Y. Wilks, and M. Stevenson. Proceedings of the 17th International Conference on Computational
Linguistics and 36th Annual Meeting of the Association for Computational
Linguistics (COLING-ACL-98), (1998)
?. Proceedings of the 14th Annual International ACM SIGIR Conference
on Research and Development in Information Retrieval (SIGIR-91), page 202-210. Chicago, USA, (1991)
A. Rauber, and D. Merkl. Proceedings of 10th International Conference Database and Expert
Systems Applications (DEXA-99). Lecture Notes in Computer Science
Vol.1677, page 302--311. Berlin, Germany, Springer-Verlag, (1999)