%0 Journal Article %A Sichler, Jiří %T Category of commutative groupoids is binding %J Commentationes Mathematicae Universitatis Carolinae %D 1967 %P 753-755 %V 08 %N 4 %I mathdoc %U http://geodesic.mathdoc.fr/item/CMUC_1967__8_4_a10/ %G en %F CMUC_1967__8_4_a10