A. Nguyen, and W. Wobcke. Proceedings of the 10th international conference on Intelligent user interfaces, page 137--144. New York, NY, USA, ACM, (2005)
T. Heinroth, D. Denich, and W. Minker. Universal Access in Human-Computer Interaction. Applications and Services, volume 6768 of Lecture Notes in Computer Science, chapter 5, Springer-Verlag, Berlin/Heidelberg, (2011)