University of Pittsburgh
University of Pittsburgh: Discrete Mathematics Graphs
A pdf version of lecture notes covering a variety of graphical representations.
Other
Study.com: Graphs in Discrete Math: Definition, Types & Uses
This lesson will define graphs in discrete mathematics, and look at some different types. You'll also see how these types of graphs can be used in some real-world applications.
Other
Discrete Mathematics: Euler Paths and Circuits
Explanation and questions about Euler paths and circuits with solutions to the questions.