%0 Journal Article
%A V. A. Il'in
%T Necessary and sufficient conditions for a subsystem of the eigen- and associated functions of a Keldys bundle of ordinary differential operators to be a basis
%J Doklady Akademii Nauk
%D 1976
%P 796-799
%V 227
%N 4
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1976_227_4_a5/
%G ru
%F DAN_1976_227_4_a5