TY  - JOUR
AU  - Hidekazu Ito
TI  - Integrability of Hamiltonian systems and Birkhoff normal forms in the simple resonance case.
JO  - Mathematische Annalen
PY  - 1992
SP  - 411
EP  - 444
VL  - 292
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MAN_1992__292_2_164922/
ID  - MAN_1992__292_2_164922
ER  -