A historical reference, along with a solution and interesting links for the Konigsberg bridge problem is found at this site:

http://mathforum.org/isaac/problems/bridgesol1.html

This site provides a nice discussion of minimum spanning trees.

http://www.people.vcu.edu/~gasmerom/MAT131/mst.html

This is a nice interactive demonstration of Krukal’s algorithm:

http://students.ceid.upatras.gr/~papagel/project/kruskal.htm

Problem 45 presents “The Oracle of Bacon.” You will have fun with this site playing this trivia game.

http://oracleofbacon.org/