@article{05829230, title = {A note on periodic solutions of second order nonautonomous singular coupled systems.}, journal = {Mathematical Problems in Engineering}, volume = {2010}, year = {2010}, doi = {10.1155/2010/458918}, zbl = {1208.34051}, language = {en}, url = {http://dml.mathdoc.fr/item/05829230} }
Cao, Zhongwei; Yuan, Chengjun; Jiang, Daqing; Wang, Xiaowei. A note on periodic solutions of second order nonautonomous singular coupled systems.. Mathematical Problems in Engineering, Tome 2010 (2010) . doi : 10.1155/2010/458918. http://gdmltest.u-ga.fr/item/05829230/