Junqing Yang Min Zhou Xiaohong An Lining Zhang Offset Approximation Algorithm for Subdivision Surfaces. 216-221 2007 SNPD (3) http://doi.ieeecomputersociety.org/10.1109/SNPD.2007.394 conf/snpd/2007 db/conf/snpd/snpd2007-3.html#YangZAZ07