%0 Journal Article
%A S. V. Buyalo
%T Euclidean planes in three-dimensional manifolds of nonpositive curvature
%J Matematičeskie zametki
%D 1988
%P 103-114
%V 43
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MZM_1988_43_1_a11/
%G ru
%F MZM_1988_43_1_a11