Joëlle Coutaz, Laurence Nigay, Daniel Salber, Ann Blandford, Jon May, Richard M. Young. Four easy pieces for assessing the usability of multimodal interaction: the CARE properties. In Knut Nordby, Per H. Helmersen, David J. Gilmore, Svein A. Arnesen, editors, Human-Computer Interaction, INTERACT 95, IFIP TC13 Interantional Conference on Human-Computer Interaction, 27-29 June 1995, Lillehammer, Norway. IFIP Conference Proceedings, pages 115-120, Chapman & Hall, 1995.