http://www.ecp6.jussieu.fr/pageperso/bondy/bondy.html
Graph Theory with Applications 
J.A. Bondy and U.S.R. Murty


S.C. Locke's Graph Theory web page
http://www.math.fau.edu/locke/GRAPHTHE.HTM


http://dimacs.rutgers.edu/~hochberg/undopen/graphtheory/graphtheory.html

http://dimacs.rutgers.edu/~hochberg/undopen/graphtheory/graphtheory.html

http://www.math.fau.edu/locke/Unsolved.htm

http://people.freenet.de/Emden-Weinert/graphs.html#OpenProblems

http://archives.math.utk.edu/topics/discreteMath.html



http://www.utm.edu/cgi-bin/caldwell/tutor/departments/math/graph/intro

1.	Old Königsberg had seven bridges (marked a through g in the 
sketch). The townspeople wondered if was possible to take a walk around 
the town in such a way as to cross each of the seven bridges exactly once. 
What do you think? 

2.	How many colors do we need to color a map so that every pair of 
countries with a border in common have different colors? 

3.	Given a map of several cities and the roads between them, is it 
possible for a traveling salesman to visit (pass through) each of the 
cities exactly once?