Philip R. Cohen David McGee Sharon L. Oviatt Lizhong Wu Josh Clow Rob King Simon Julier Lawrence J. Rosenblum Multimodal Interaction for 2D and 3D Environments. 10-13 1999 19 IEEE Computer Graphics and Applications 4 http://doi.ieeecomputersociety.org/10.1109/38.773958 db/journals/cga/cga19.html#CohenMOWCKJR99