References

A NEW APPROACH TO PROBLEM OF PLANAR GRAPH COLORABILITY


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[2] K. Appel, W. Haken and J. Koch, Every planar map is four colorable, Part II: Reducibility, Illinois J. Math. 21 (1977), 491-567.

[3] K. Appel and W. Haken, Every planar map is four colorable, Contemporary Mathematics, Amer. Math. Soc. 98 (1989).

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[8] G. Trigiante and D. Trigiante, On the Coloring of Maximal Planar Graphs, In Proceeding II Int. Symposium on ‘Problemi dell\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'Analisi e della Fisica Matematica\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\' held in Taormina Oct 1998, ARACNE 2000.

[9] G. Trigiante and D. Trigiante, On the Constraints of Internal Chains in Graph Coloring, Report of Math. Dept. University of Florence, N. 19-2000.