%0 Journal Article %A Koman, Milan %T Extremal Crossing Numbers of Complete $k$-Chromatic Graphs %J Mathematica slovaca %D 1970 %P 315-325 %V 20 %N 4 %I mathdoc %U http://geodesic.mathdoc.fr/item/MASLO_1970__20_4_a10/ %G en %F MASLO_1970__20_4_a10