A. Hotho, R. Jäschke, C. Schmitz, and G. Stumme. Proceedings of the 3rd European Semantic Web Conference (accepted for publication), Budva, Montenegro, (June 2006)
R. Pichler, A. Polleres, S. Skritek, and S. Woltran. 4th International Conference on Web Reasoning and Rule Systems, volume 6333 of Lecture Notes in Computer Science, page 133-148. Springer, (2010)