%0 Journal Article
%A A.H. Clifford
%A T.E. Hall
%T A characterization of ...-classes of semigroups as partial groupoids.
%J Semigroup forum
%D 1974
%P 246-254
%V 6
%I mathdoc
%U http://geodesic.mathdoc.fr/item/SF_1974__6_133980/
%F SF_1974__6_133980