Graph theory has strong historical roots in Mathematics. Its birth is usually associated with the four-color problem posed by Francis Guthrie in 1852, but its real origin probably goes back to the Seven Bridges of Konigsberg Problem proved by Leonhard Euler in 1736. In general, a graph is a nonempty set of points (vertices) and the most basic information preserved by any graph structure refers to adjacency relationships (edges) between some pairs of points. In the simplest graphs, edges do not have to hold any attributes, except their endpoints, but in more sophisticated graph structures, edges can be associated with a direction or assigned a label. There are several reasons for the acceleration of interest in graph theory. Graph theory has...