%0 Journal Article
%A Beno Eckmann
%A Urs Stammbach
%A Peter J. Hilton
%T On the Homology Theory of Central Group Extensions: I - The Commutator Map and Stem Extensions
%J Commentarii mathematici Helvetici
%D 1972
%P 102-122
%V 47
%I mathdoc
%U http://geodesic.mathdoc.fr/item/CMH_1972__47_139503/
%F CMH_1972__47_139503