L. Chen, und P. Pu. Proceedings of the National Conference on Artificial Intelligence, 1, Seite 157--162. American Association for Artificial Intelligence, Menlo Park, CA
94025-3496, United States, (2006)Human Computer Interaction Group, School of Computer and Communication
Sciences, Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015
Lausanne, Switzerland.