S. Braun, C. Schora, and V. Zacharias. 5th International Conference on Semantic Systems (I-SEMANTICS 2009), Proceedings of I-KNOW 09 and I-SEMANTICS 09, page 445-454. Graz, Austria, Verlag der Technischen Universitt Graz, (2009)
S. Lohmann, S. Thalmann, A. Harrer, and R. Maier. Proceedings of I-KNOW ´08, 8th International Conference on Knowledge Management, Graz, Austria, September 3-5, page 304-312. (2008)