Yong-qing Li Ying-Lin Ke Wei-Shi Li Qunsheng Peng Jian-Rong Tan Termination criterion for subdivision of triangular Bézier patch. 67-74 2002 26 Computers & Graphics 1 http://dx.doi.org/10.1016/S0097-8493(01)00158-3 db/journals/cg/cg26.html#LiKLPT02