1. Constellations et Propriétés Algèbriques des Graphes Topologiques;Jacques,1969
2. Jenkyns, T. A., See [GJ1].
3. Voltage graphs;Gross;Discrete Math.,1974
4. Branched coverings of graph imbeddings;Gross;Bull. Amer. Math. Soc.,1973
5. The topological theory of current graphs;Gross;J. Combinatorial Theory B,1974