1. P.S. Aleksandrov, Combinatorial Topology (in three volumes), translated from the Russian. Kombinatornaya Topologiya 1947, by Horace Komm, Graylock Press, Rochester, 1956 1st volume, 1957 2nd volume, and 1960 3rd volume. Reproduced by Dover Publications, New York, 1998.
2. Euclidean Geometry and Convexity;Benson,1966
3. An elementary geometric nonstandard proof of the Jordan curve theorem;Bertoglio;Geom. Dedicata,1994
4. Triangulating a simple polygon in linear time;Chazelle;Discrete Comput. Geom.,1991
5. What is Mathematics?;Courant,2003