%0 Journal Article
%A M. Breen
%T Principal ideals in the semigroup of binary relations  on a finite set: What happens when one element is added to the set.
%J Semigroup forum
%D 1992
%P 129-132
%V 44
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/SF_1992__44_1_135137/
%F SF_1992__44_1_135137