%0 Journal Article
%A J. Almeida
%T On the membership problem for pseudo-varieties of commutative semigroups.
%J Semigroup forum
%D 1991
%P 47-52
%V 42
%N 3
%I mathdoc
%U http://geodesic.mathdoc.fr/item/SF_1991__42_3_135062/
%F SF_1991__42_3_135062