%0 Journal Article %A Havel, Václav %T Construction of certain systems with two compositions %J Commentationes Mathematicae Universitatis Carolinae %D 1965 %P 413-428 %V 06 %N 4 %I mathdoc %U http://geodesic.mathdoc.fr/item/CMUC_1965__6_4_a3/ %G en %F CMUC_1965__6_4_a3