@article{01230055, title = {On the existence of a periodic solution of a nonlinear ordinary differential equation.}, journal = {International Journal of Mathematics and Mathematical Sciences}, volume = {21}, year = {1998}, pages = {767-774}, doi = {10.1155/S0161171298001070}, zbl = {0923.34046}, language = {en}, url = {http://dml.mathdoc.fr/item/01230055} }
Chu, Hsin; Ding, Sunhong. On the existence of a periodic solution of a nonlinear ordinary differential equation.. International Journal of Mathematics and Mathematical Sciences, Tome 21 (1998) pp. 767-774. doi : 10.1155/S0161171298001070. http://gdmltest.u-ga.fr/item/01230055/