Pankaj Khanna Mel Slater Jesper Mortensen Insu Yu A Non-parametric Guide for Radiance Sampling in Global Illumination. 41-48 2007 conf/IEEEcgiv/2007 CGIV http://doi.ieeecomputersociety.org/10.1109/CGIV.2007.9 db/conf/IEEEcgiv/cgiv2007.html#KhannaSMY07