@article{10_4064_ap93_1_6,
     author = {Changxiu Song},
     title = {Positive periodic solutions of
 functional differential equations with infinite delay},
     journal = {Annales Polonici Mathematici},
     pages = {75--83},
     publisher = {mathdoc},
     volume = {93},
     number = {1},
     year = {2008},
     doi = {10.4064/ap93-1-6},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/ap93-1-6/}
}