Reconfirmation of Two Results on Disjoint Empty Convex Polygons. - Liping Wu 001; Ren Ding 002 (CJCDGCGT, 2005)

On the number of empty convex quadrilaterals of a finite set in the plane. - Liping Wu 001; Ren Ding 002 (Appl. Math. Lett., 2008)