I. Horrocks, U. Sattler, and S. Tobies. Proceedings of the 6th International Conference on Logic for Programming and Automated Reasoning (LPAR'99), 1705, page 161--180. Springer-Verlag, (1999)
I. Horrocks, U. Sattler, and S. Tobies. Proceedings of the 6th International Conference on Logic for Programming and Automated Reasoning (LPAR'99), 1705, page 161--180. Springer-Verlag, (1999)