1. J. Akiyama, Forbidden subgraphs for planar total graphs, J. Combinatorics Information System Sciences, 3 (1978), 255–260.
2. M. Behzad, A criterion for the planarity of total graph, Proc. Cambridge Philos. Soc., 63 (1967), 679–681.
3. M. Borowiecki and D. Michalak, On planarity and outerplanarity of total, line and middle graphs, Report Nr. IF-6-79 WSI nż., Zielona Góra, (1979).
4. F. Harary, Graph Theory, Addison Wesley, Reading, Mass., (1969).
5. D. Michalak, On line graphs with coarseness number equal 1, Disc. Math., (to appear).