@article{05237456, title = {Multiple periodic solutions to nonlinear discrete Hamiltonian systems.}, journal = {Advances in Difference Equations [electronic only]}, volume = {2007}, year = {2007}, doi = {10.1155/2007/41830}, zbl = {1152.39013}, language = {en}, url = {http://dml.mathdoc.fr/item/05237456} }
Zheng, Bo. Multiple periodic solutions to nonlinear discrete Hamiltonian systems.. Advances in Difference Equations [electronic only], Tome 2007 (2007) . doi : 10.1155/2007/41830. http://gdmltest.u-ga.fr/item/05237456/