%0 Journal Article
%A B. E. Kantor
%T On~the problem of the normal image of a~complete surface of negative curvature
%J Sbornik. Mathematics
%D 1970
%P 197-200
%V 11
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/item/SM_1970_11_2_a4/
%G en
%F SM_1970_11_2_a4