%0 Journal Article
%A N. I. Popivanov
%T Equations of mixed type with two lines of degeneracy in unbounded domains. I.~Imbedding theorem. Uniqueness theorem
%J Differencialʹnye uravneniâ
%D 1978
%P 304-317
%V 14
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1978_14_2_a11/
%G ru
%F DE_1978_14_2_a11