T. Scheffler, R. Roller, and N. Reithinger. Proceedings of the 6th IJCAI Workshop on Knowledge and Reasoning in Practical Dialogue Systems, Pasadena, CA, USA, page 93-98. (2009)
R. Schneider, and P. Heisterkamp. Proceedings of the ISCA Tutorial and Research Workshop (ITRW) on Interactive Dialogue in Multi-Modal Systems (IDS-02): Multi-Modal Dialogue in Mobile Environments. Kloster Irsee, Germany, (2002)