www.hsor.org/what_is_or.cfm This site discusses the history of OR and some of the areas where OR is being applied. Be sure to follow the “Networks Routing” link to see applications of the Chinese postman problem.

www.geom.uiuc.edu/~doty/applications This web page provides some examples of how to apply Euler circuits.

http://www-history.mcs.st-andrews.ac.uk/Mathematicians/Euler.html This essay discusses the numerous contributions that Euler made to mathematics and provides biographical information about him.

www.ams.org/samplings/feature-column/fcarc-urban-geom This web page includes an introduction to how graph theory has provided tools for urban operations research.