@article{GDZPPN002207680,
title = {Perturbations of the spherical pendulum and Abelian integrals.},
journal = {Journal f\"ur die reine und angewandte Mathematik},
volume = {405},
year = {1990},
pages = {114-135},
zbl = {0692.58031},
url = {http://dml.mathdoc.fr/item/GDZPPN002207680}
}
Horozov, E. Perturbations of the spherical pendulum and Abelian integrals.. Journal für die reine und angewandte Mathematik, Tome 405 (1990) pp. 114-135. http://gdmltest.u-ga.fr/item/GDZPPN002207680/