Xiaomin Chen János Pach Mario Szegedy Gábor Tardos Delaunay graphs of point sets in the plane with respect to axis-parallel rectangles. 94-101 2008 SODA http://doi.acm.org/10.1145/1347082.1347093 conf/soda/2008 db/conf/soda/soda2008.html#ChenPST08