J. Ontrup, und H. Ritter. Proceedings of PKDD-01, 5th European Conference on Principles and Practice of Knowledge Discovery in Databases, Seite 338--349. Springer, LNAI 2168, (2001)
J. Suzuki, T. Hirao, Y. Sasaki, und E. Maeda. ACL '03: Proceedings of the 41st Annual Meeting on Association for Computational Linguistics, Seite 32--39. Morristown, NJ, USA, Association for Computational Linguistics, (2003)