J. Kreutel. Proceedings of the 8th SIGdial Workshop on Discourse and Dialogue, Seite 235–238. Association for Computational Linguistics (ACL), (September 2007)
J. Van den Bergh, und K. Coninx. Proceedings of the 6th international conference on Task models and diagrams for user interface design, Seite 98--111. Berlin/Heidelberg, Springer-Verlag, (2007)