References
Biggs, Norman L., E. K. Lloyd, and Robin J. Wilson. Graph Theory: 1736-1936. Oxford: Clarendon Press, 1976.
Dunham, William. Euler: The Master of Us All. Washington: The Mathematical Association of America, 1999.
"History of Mathematics: On Leonhard Euler (1707-1783)." ScienceWeek (2003). 6 Nov. 2005.
Hopkins, Brian, and Robin Wilson. "The Truth about Königsberg." College Mathematics Journal (2004), 35, 198-207.
"Konigsberg Bridges." The MacTutor History of Mathematics Archive:
http://www-history.mcs.st- and.ac.uk/history/Miscellaneous/other_links/Konigsberg.html
Teo Paoletti, "Leonard Euler's Solution to the Konigsberg Bridge Problem - References," Convergence (May 2011)