%0 Journal Article
%A V. A. Sadovnichii
%A V. A. Lyubishkin
%T Trace formulas and perturbation theory
%J Doklady Akademii Nauk
%D 1988
%P 1064-1066
%V 300
%N 5
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1988_300_5_a7/
%G ru
%F DAN_1988_300_5_a7