1. Hull, a program for convex hulls,
http://www.netlib.org/voronoi/hull.html
2. Qhull,
http://www.qhull.org/
3. Cgal, Computational Geometry Algorithms Library,
http://www.cgal.org
4. Core number library,
http://cs.nyu.edu/exact/core_pages
5. Leda, Library for efficient data types and algorithms,
http://www.algorithmic-solutions.com/enleda.htm