Problém čtyř barev, barvení grafů, rovinné grafy
Teorie grafů, 1736–1963, GDML_Books, (1997), p. 51-69 / Harvested from
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@inbook{400870,
     title = {Probl\'em \v cty\v r barev, barven\'\i\ graf\r u, rovinn\'e grafy},
     booktitle = {Teorie graf\r u, 1736--1963},
     series = {GDML\_Books},
     publisher = {Prometheus},
     address = {Praha},
     year = {1997},
     pages = {51-69},
     url = {http://dml.mathdoc.fr/item/400870}
}

 (éd.). Problém čtyř barev, barvení grafů, rovinné grafy, dans Teorie grafů, 1736–1963, GDML_Books,  (1997), pp. 51-69. http://gdmltest.u-ga.fr/item/400870/