%0 Journal Article
%A P. A. Kuchment
%T Periodic perturbations that preserve the law of dispersion of a differential operator
%J Differencialʹnye uravneniâ
%D 1986
%P 1641-1642
%V 22
%N 9
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1986_22_9_a30/
%G ru
%F DE_1986_22_9_a30