%0 Journal Article
%A H. Pei
%T Equivalences, a-semigroups and a-congruences.
%J Semigroup forum
%D 1994
%P 49-58
%V 49
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/item/SF_1994__49_2_135333/
%F SF_1994__49_2_135333