@article{01780534, title = {Positive periodic solutions of nonautonomous functional differential equations depending on a parameter.}, journal = {Abstract and Applied Analysis}, volume = {7}, year = {2002}, pages = {279-286}, doi = {10.1155/S1085337502000878}, zbl = {1007.34066}, language = {en}, url = {http://dml.mathdoc.fr/item/01780534} }
Zhang, Guang; Cheng, Sui Sun. Positive periodic solutions of nonautonomous functional differential equations depending on a parameter.. Abstract and Applied Analysis, Tome 7 (2002) pp. 279-286. doi : 10.1155/S1085337502000878. http://gdmltest.u-ga.fr/item/01780534/