TY  - JOUR
AU  - Alan Weinstein
TI  - Normal Modes for Nonlinear Hamiltonian Systems.
JO  - Inventiones mathematicae
PY  - 1973
SP  - 47
EP  - 58
VL  - 20
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/IM_1973__20_142203/
ID  - IM_1973__20_142203
ER  -