The author applies a generalized Leggett-Williams fixed point theorem to the study of the nonlinear functional differential equation . Sufficient conditions are established for the existence of multiple positive periodic solutions.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-ap93-1-6, author = {Changxiu Song}, title = {Positive periodic solutions of functional differential equations with infinite delay}, journal = {Annales Polonici Mathematici}, volume = {93}, year = {2008}, pages = {75-83}, zbl = {1142.34363}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-ap93-1-6} }
Changxiu Song. Positive periodic solutions of functional differential equations with infinite delay. Annales Polonici Mathematici, Tome 93 (2008) pp. 75-83. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-ap93-1-6/