@article{05019234, title = {Multiple periodic solutions to a class of second-order nonlinear mixed-type functional differential equations.}, journal = {International Journal of Mathematics and Mathematical Sciences}, volume = {2005}, year = {2005}, pages = {2689-2702}, doi = {10.1155/IJMMS.2005.2689}, zbl = {1098.34058}, language = {en}, url = {http://dml.mathdoc.fr/item/05019234} }
Shu, Xiao-Bao; Xu, Yuan-Tong. Multiple periodic solutions to a class of second-order nonlinear mixed-type functional differential equations.. International Journal of Mathematics and Mathematical Sciences, Tome 2005 (2005) pp. 2689-2702. doi : 10.1155/IJMMS.2005.2689. http://gdmltest.u-ga.fr/item/05019234/