Linear homogeneous Diophantine equations and magic labelings of graphs
Richard P. Stanley · Duke Mathematical Journal · 1973
Hence G is a pseudograp in the terminology of [10]. We shall denote the set of vertices of G by V, the set of edges by E, the number IVI of vertices by p, and the number IEI of edges by q. Also if an edge e is incident to a vertex v, we write v e. Any undefined graph-theoretical terminology used here may be