Appel, Kenneth; Haken, Wolfgang Every planar map is four colorable. (English) Zbl 0357.05043 J. Recreational Math. 9(1976), 161-169 (1977). Page: −5 −4 −3 −2 −1 ±0 +1 +2 +3 +4 +5 Show Scanned Page Cited in 1 ReviewCited in 9 Documents MSC: 05C15 Coloring of graphs and hypergraphs 05-02 Research exposition (monographs, survey articles) pertaining to combinatorics 05-03 History of combinatorics PDF BibTeX XML Cite \textit{K. Appel} and \textit{W. Haken}, J. Recreat. Math. 9, 161--169 (1977; Zbl 0357.05043)