T. Sederberg, and E. Greenwood. Proceedings of the 19th annual conference on Computer graphics and interactive techniques, page 25--34. New York, NY, USA, ACM, (1992)
H. Hoppe. SIGGRAPH '97: Proceedings of the 24th annual conference on Computer graphics and interactive techniques, page 189--198. New York, NY, USA, ACM Press/Addison-Wesley Publishing Co., (1997)