%0 Journal Article
%A John N. Mather
%T Commutators of diffeomorphisms, III: a group which is not perfect.
%J Commentarii mathematici Helvetici
%D 1985
%P 122-124
%V 60
%I mathdoc
%U http://geodesic.mathdoc.fr/item/CMH_1985__60_140003/
%F CMH_1985__60_140003