@article{GDZPPN002436264,
title = {Perturbation of Hamiltonian Systems with Keplerian Potentials.},
journal = {Mathematische Zeitschrift},
volume = {202},
year = {1989},
pages = {227-242},
zbl = {0653.34032},
url = {http://dml.mathdoc.fr/item/GDZPPN002436264}
}
Ambrosetti, Antonio; Coti Zelati, V. Perturbation of Hamiltonian Systems with Keplerian Potentials.. Mathematische Zeitschrift, Tome 202 (1989) pp. 227-242. http://gdmltest.u-ga.fr/item/GDZPPN002436264/