Andrew T. Duchowski Nathan Cournia Brian Cumming Daniel McCallum Anand K. Gramopadhye Joel S. Greenstein Sajay Sadasivan Richard A. Tyrrell Visual deictic reference in a collaborative virtual environment. 35-40 2004 conf/etra/2004 ETRA http://doi.acm.org/10.1145/968363.968369 db/conf/etra/etra2004.html#DuchowskiCCMGGST04