%0 Journal Article
%A G. A. Leonov
%T The necessity of a frequency condition for the absolute stability of stationary systems in the critical case of a pair of pure imaginary roots
%J Doklady Akademii Nauk
%D 1970
%P 756-759
%V 193
%N 4
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1970_193_4_a4/
%G ru
%F DAN_1970_193_4_a4