%0 Journal Article %A V. A. Pliss %T The phenomenon of convergence in non-linear periodic systems %J Doklady Akademii Nauk %D 1961 %P 301-304 %V 138 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/item/DAN_1961_138_2_a13/ %G ru %F DAN_1961_138_2_a13