%0 Journal Article
%A I. V. Ostrovskii
%T A generalization of a theorem stated by M.\,G.~Krein
%J Doklady Akademii Nauk
%D 1957
%P 742-745
%V 116
%N 5
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1957_116_5_a6/
%G ru
%F DAN_1957_116_5_a6