The Four -Color Theorem : Graph and Map

http://dmentrard.free.fr/GEOGEBRA/Maths/Export5/FourcolorMD.html
[url=http://dmentrard.free.fr/GEOGEBRA/Maths/Export5/FourcolorMD.html]http://dmentrard.free.fr/GEOGEBRA/Maths/Export5/FourcolorMD.html[/url]
– Daniel Mentrard

Information: The Four -Color Theorem : Graph and Map