%0 Journal Article %A Vougiouklis, T. %T The set of hypergroups with operators which are constructed from a set with two elements %J Acta Universitatis Carolinae. Mathematica et Physica %D 1981 %P 7-10 %V 22 %N 1 %U http://geodesic.mathdoc.fr/item/AUCMP_1981_22_1_a2/ %G en %F AUCMP_1981_22_1_a2