%0 Journal Article
%A Santos, J. C. 
%T When is a group homomorphism a covering homomorphism? 
%J Extracta mathematicae
%D 2007
%P 325-330
%V 22
%N 3
%I mathdoc
%U http://geodesic.mathdoc.fr/item/EXMATH_2007_2007_1_a22/
%G en
%F EXMATH_2007_2007_1_a22