Dominique Attali Herbert Edelsbrunner Yuriy Mileyko Weak witnesses for Delaunay triangulations of submanifolds. 143-150 2007 conf/sma/2007 Symposium on Solid and Physical Modeling http://doi.acm.org/10.1145/1236246.1236267 db/conf/sma/spm2007.html#AttaliEM07