Chojnacki, Chaim A contribution to the four color problem. (English) Zbl 0061.41305 Am. J. Math. 64, 36-54 (1942). Page: −5 −4 −3 −2 −1 ±0 +1 +2 +3 +4 +5 Show Scanned Page Cited in 2 Documents Keywords:topology PDF BibTeX XML Cite \textit{C. Chojnacki}, Am. J. Math. 64, 36--54 (1942; Zbl 0061.41305) Full Text: DOI