%0 Journal Article
%A D. Mittenhuber
%T Semigroups in the simply connected  covering of SL(2).
%J Semigroup forum
%D 1993
%P 379-387
%V 46
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/SF_1993__46_1_135244/
%F SF_1993__46_1_135244