%0 Journal Article
%A V. I. Filippenko
%T On the multiplicity of a spectrum of a first-order selfadjoint differential operator
%J Differencialʹnye uravneniâ
%D 1981
%P 1135-1138
%V 17
%N 6
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1981_17_6_a19/
%G ru
%F DE_1981_17_6_a19