Harry Bunt René M. C. Ahn Robbert-Jan Beun Tijn Borghuis Cornelius W. A. M. van Overveld Multimodal Cooperation with the DENK System. 39-67 1995 conf/cmc/1995 Multimodal Human-Computer Communication http://dx.doi.org/10.1007/BFb0052312 db/conf/cmc/cmc1995.html#BuntABBO95