Hee-Kap Ahn Sang Won Bae Otfried Cheong Joachim Gudmundsson Aperture-angle and Hausdorff-approximation of convex figures. 37-45 2007 conf/compgeom/2007 Symposium on Computational Geometry http://doi.acm.org/10.1145/1247069.1247076 db/conf/compgeom/compgeom2007.html#AhnBCG07