@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/