%0 Journal Article
%A A. G. Surkov
%T Sharp bounds for characteristic indices of second-order linear systems with bounded perturbations
%J Differencialʹnye uravneniâ
%D 1984
%P 792-797
%V 20
%N 5
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DE_1984_20_5_a5/
%G ru
%F DE_1984_20_5_a5