%0 Journal Article
%A A. L. Verner
%T On the extrinsic geometry of elementary complete surfaces with nonpositive curvature. I
%J Sbornik. Mathematics
%D 1967
%P 205-224
%V 3
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/item/SM_1967_3_2_a4/
%G en
%F SM_1967_3_2_a4