George W. Fitzmaurice Justin Matejka Igor Mordatch Azam Khan Gordon Kurtenbach Safe 3D navigation. 7-15 2008 SI3D http://doi.acm.org/10.1145/1342250.1342252 conf/si3d/2008 db/conf/si3d/si3d2008.html#FitzmauriceMMKK08