Geodesic
Positive periodic solutions of functional differential equations and population models
Electronic journal of differential equations, Tome 2002 (2002)
In this paper, we employ Krasnosel'skii's fixed point theorem for cones to study the existence of positive periodic solutions to a system of infinite delay equations,

$ x'(t) = A(t)x(t) + f(t,x_t). $

We prove two general theorems and establish new periodicity conditions for several population growth models.
Classification : 34K13, 92B05
Keywords: functional differential equations, positive periodic solution, population models 
@article{EJDE_2002__2002__a216,
     author = {Jiang,  Daqing and Wei,  Junjie and Zhang,  Bo},
     title = {Positive periodic solutions of functional differential equations and population models},
     journal = {Electronic journal of differential equations},
     year = {2002},
     volume = {2002},
     zbl = {1010.34065},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2002__2002__a216/}
}
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AU  - Zhang,  Bo
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Jiang,  Daqing; Wei,  Junjie; Zhang,  Bo. Positive periodic solutions of functional differential equations and population models. Electronic journal of differential equations, Tome 2002 (2002). http://geodesic.mathdoc.fr/item/EJDE_2002__2002__a216/