M. Pucher, F. Neubarth, and D. Schabus. Proceedings of the 12th international conference on Computers helping people with special needs (ICCHP), page 361-366. Vienna, Austria, (July 2010)
R. Vilimek, T. Hempel, and B. Otto. Human-Computer Interaction: HCI Intelligent Multimodal Interaction Environments, 12th International Conference, HCI International 2007, Beijing, China, Proceedings, Part III, volume 4552 of Lecture Notes in Computer Science, Springer, Berlin, (2007)
Y. Wang, and S. Hamerich. Recent Trends in Discourse and Dialogue, volume 39 of Text, Speech and Language Technology, chapter 2, Springer, Dordrecht, (2008)
R. Pieraccini, and J. Huerta. Recent Trends in Discourse and Dialogue, volume 39 of Text, Speech and Language Technology, chapter 1, Springer, Dordrecht, (2008)