%0 Journal Article
%A D. P. Kostomarov
%T On boundary problems for eigen-values and characteristic functions of ordinary differential equations 

%J Doklady Akademii Nauk
%D 1957
%P 230-233
%V 115
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1957_115_2_a7/
%G ru
%F DAN_1957_115_2_a7