%0 Journal Article
%A V. V. Ryzhkov
%T Tangentially degenerate surfaces
%J Doklady Akademii Nauk
%D 1960
%P 20-22
%V 135
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1960_135_1_a3/
%G ru
%F DAN_1960_135_1_a3