%0 Journal Article
%A È. M. Saak
%T Approximation theorems for differential equations
%J Doklady Akademii Nauk
%D 1965
%P 1249-1252
%V 165
%N 6
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1965_165_6_a7/
%G ru
%F DAN_1965_165_6_a7