%0 Journal Article
%A Alan Weinstein
%T Normal Modes for Nonlinear Hamiltonian Systems.
%J Inventiones mathematicae
%D 1973
%P 47-58
%V 20
%I mathdoc
%U http://geodesic.mathdoc.fr/item/IM_1973__20_142203/
%F IM_1973__20_142203