@article{05237441, title = {Existence of periodic and subharmonic solutions for second-order }, journal = {Advances in Difference Equations [electronic only]}, volume = {2007}, year = {2007}, doi = {10.1155/2007/42530}, zbl = {1148.39002}, language = {en}, url = {http://dml.mathdoc.fr/item/05237441} }
Chen, Peng; Fang, Hui. Existence of periodic and subharmonic solutions for second-order . Advances in Difference Equations [electronic only], Tome 2007 (2007) . doi : 10.1155/2007/42530. http://gdmltest.u-ga.fr/item/05237441/