Tomas Porter Pat Hanrahan James F. Blinn Nick England Rob Pike Flip Phillips Special section: SIGGRAPH bowl. 501-529 1990 conf/siggraph/1990panel SIGGRAPH (Panels) http://doi.acm.org/10.1145/328750.328768 db/conf/siggraph/siggraph1990panel.html#PorterHBEPP90