Max Wardetzky Saurabh Mathur Felix Kälberer Eitan Grinspun Discrete laplace operators: no free lunch. 33-37 2007 conf/sgp/2007 Symposium on Geometry Processing http://doi.acm.org/10.1145/1281991.1281995 db/conf/sgp/sgp2007.html#WardetzkyMKG07