%0 Journal Article
%A F. S. Rofe-Beketov
%T A finiteness test for the number of discrete levels which can be introduced into the gaps of the continuous 

%J Doklady Akademii Nauk
%D 1964
%P 515-518
%V 156
%N 3
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1964_156_3_a8/
%G ru
%F DAN_1964_156_3_a8