A. Zündorf, and J. Dreyer. Fujaba Days 2009: proceedings of the 7th international Fujaba days, page 56-58. Technische Universiteit Eindhoven, (November 2009)
P. Cimiano, and J. Völker. Proceedings of the 10th International Conference on Applications of Natural Language to Information Systems (NLDB), volume 3513 of Lecture Notes in Computer Science, page 227-238. Alicante, Spain, Springer, (June 2005)
M. de Marneffe, B. MacCartney, and C. Manning. Proceedings of the IEEE / ACL 2006 Workshop on Spoken Language Technology, The Stanford Natural Language Processing Group, (2006)