%0 Journal Article
%A S. M. Vishik
%T On invariant characteristics of quadratically nonlinear systems of cascade type
%J Doklady Akademii Nauk
%D 1976
%P 1269-1272
%V 228
%N 6
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1976_228_6_a1/
%G ru
%F DAN_1976_228_6_a1