%0 Journal Article %A V. A. Pliss %T Analysis of the necessity of the conditions of Smale and Robbin for structural stability for periodic systems of differential equations %J Differencialʹnye uravneniâ %D 1972 %P 972-983 %V 8 %N 6 %I mathdoc %U http://geodesic.mathdoc.fr/item/DE_1972_8_6_a3/ %G ru %F DE_1972_8_6_a3