%0 Journal Article
%A R. Piergallini
%T Covering homotopy 3-spheres.
%J Commentarii mathematici Helvetici
%D 1992
%P 287-292
%V 67
%N 3
%I mathdoc
%U http://geodesic.mathdoc.fr/item/CMH_1992__67_3_140269/
%F CMH_1992__67_3_140269