@article{01463547, title = {Periodic solutions of neutral Duffing equations.}, journal = {Electronic Journal of Qualitative Theory of Differential Equations [electronic only]}, volume = {2000}, year = {2000}, zbl = {0954.34060}, language = {en}, url = {http://dml.mathdoc.fr/item/01463547} }
Zhang, Z.Q.; Wang, Z.C.; Yu, J.S. Periodic solutions of neutral Duffing equations.. Electronic Journal of Qualitative Theory of Differential Equations [electronic only], Tome 2000 (2000) . http://gdmltest.u-ga.fr/item/01463547/