References
- J. A. Bondy and U. S. R. Murty, Graph Theory with Applications, Elsevier Publishing Co., 1977.
- J. Malkevith, Properties of planar graphs with uniform vertex and face structure, Memoirs of the A.M.S., American Mathematical Society, 1970.
- G. Chartrand and L. Lensniak, Graphs and Digraphs, Wadsworth and Books, California, 1979.