%0 Journal Article %A Havel, Václav %T Ternary halfgroupoids and coordinatization %J Mathematica slovaca %D 1969 %P 102-109 %V 19 %N 2 %U http://geodesic.mathdoc.fr/item/MASLO_1969_19_2_a2/ %G en %F MASLO_1969_19_2_a2