%0 Journal Article %A O. V. Druzhinina %A A. A. Shestakov %T On the instability of an equilibrium state with respect to the first approximation of a stationary nonlinear equation in a Hilbert space %J Differencialʹnye uravneniâ %D 1999 %P 840 %V 35 %N 6 %I mathdoc %U http://geodesic.mathdoc.fr/item/DE_1999_35_6_a17/ %G ru %F DE_1999_35_6_a17