@article{GDZPPN002067439,
title = {Normal forms for Hamiltonian systems with Poisson commuting integrals - elliptic case.},
journal = {Commentarii mathematici Helvetici},
volume = {65},
year = {1990},
pages = {4-35},
zbl = {0702.58024},
url = {http://dml.mathdoc.fr/item/GDZPPN002067439}
}
Eliasson, L.H. Normal forms for Hamiltonian systems with Poisson commuting integrals - elliptic case.. Commentarii mathematici Helvetici, Tome 65 (1990) pp. 4-35. http://gdmltest.u-ga.fr/item/GDZPPN002067439/