Hao-Da Huang Yanyun Chen Xing Tong Wen-Cheng Wang Incremental wavelet importance sampling for direct illumination. 149-152 2007 VRST http://doi.acm.org/10.1145/1315184.1315211 conf/vrst/2007 db/conf/vrst/vrst2007.html#HuangCTW07