%0 Journal Article
%A George Danas
%T Crossed modules, Crossed n-fold extension of groups and Cohomology theory in Abstract Categories
%J Μαθηματική Επιθεώρηση
%D 1994
%P 3-27
%V 41
%U http://geodesic.mathdoc.fr/item/MR_1994_41_a0/
%G gr
%F MR_1994_41_a0