T. Groza, S. Handschuh, K. Möller, and S. Decker. Proceedings of the 5th European Semantic Web Conference, Berlin, Heidelberg, Springer Verlag, (June 2008)
H. Reiterer, G. Mußler, T. Mann, and S. Handschuh. Proceedings of the 23rd Annual International ACM SIGIR Conference
on Research and Developement in Information Retrieval, page 112-119. (2000)