@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/