M. Beetz, M. Buss, and D. Wollherr. KI 2007: Advances in Artificial Intelligence, volume 4667 of Lecture Notes in Artificial Intelligence, Springer, Berlin, (2007)
N. Bernsen, and L. Dybkjær. Proceedings of the International CLASS Workshop on Information Presentation and Natural Multimodal Dialogue, Verona, Italy, page 75-79. (2001)
A. Blandford, P. Curzon, J. Hyde, and G. Papatzanis. Interactive Systems: Design, Specification, and Verification, 15th International Workshop, DSV-IS 2008, Kingston, Canada, (2008)