G. Calvary, J. Coutaz, D. Thevenin, Q. Limbourg, L. Bouillon et al., A Unifying Reference Framework for multi-target user interfaces, Interacting with Computers, vol.15, issue.3, pp.289-308, 2003.
DOI : 10.1016/S0953-5438(03)00010-9
URL : http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.100.4512

J. Vanderdonckt, J. Coutaz, G. Calvary, and A. Stanciulescu, Multimodality for Plastic User Interfaces: Models, Methods, and Principles, Multimodal user interfaces: signals and communication technology, pp.61-84, 2007.
DOI : 10.1007/978-3-540-78345-9_4