@article{05791632,
title = {Infinitely many periodic solutions for nonautonomous sublinear second-order Hamiltonian systems.},
journal = {Abstract and Applied Analysis},
volume = {2010},
year = {2010},
doi = {10.1155/2010/620438},
zbl = {1203.37104},
language = {en},
url = {http://dml.mathdoc.fr/item/05791632}
}
Zhang, Peng; Tang, Chun-Lei. Infinitely many periodic solutions for nonautonomous sublinear second-order Hamiltonian systems.. Abstract and Applied Analysis, Tome 2010 (2010) . doi : 10.1155/2010/620438. http://gdmltest.u-ga.fr/item/05791632/