%0 Journal Article
%A G. Markowsky
%T Ordering D-classes and computing Schein rank is hard.
%J Semigroup forum
%D 1992
%P 373-375
%V 44
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/SF_1992__44_1_135161/
%F SF_1992__44_1_135161