@article{05637357, title = {Periodic solution of second-order Hamiltonian systems with a change sign potential on time scales.}, journal = {Discrete Dynamics in Nature and Society}, volume = {2009}, year = {2009}, doi = {10.1155/2009/328479}, zbl = {1182.34118}, language = {en}, url = {http://dml.mathdoc.fr/item/05637357} }
Su, You-Hui; Li, Wan-Tong. Periodic solution of second-order Hamiltonian systems with a change sign potential on time scales.. Discrete Dynamics in Nature and Society, Tome 2009 (2009) . doi : 10.1155/2009/328479. http://gdmltest.u-ga.fr/item/05637357/