F. Lonczewski. Proceedings of the 2nd international conference on Intelligent user interfaces, Seite 253--256. Orlando, Florida, United States, ACM Press, (1997)
L. Zettlemoyer, und R. Amant. Proceedings of the SIGCHI conference on Human factors in computing systems: the CHI is the limit, Seite 199--206. Pittsburgh, Pennsylvania, United States, ACM Press, (1999)