%0 Journal Article
%T Positive periodic solutions for second-order neutral differential equations with functional delay
%A Ernest Yankson
%J Electronic Journal of Differential Equations
%D 2012
%I Texas State University
%X We use Krasnoselskii's fixed point theorem to prove the existence of positive periodic solutions of the second-order nonlinear neutral differential equation $$ frac{d^2}{dt^2}x(t)+p(t)frac{d}{dt}x(t)+q(t)x(t) =cfrac{d}{dt}x(t- au(t))+f(t,h(x(t)),g(x(t- au(t)))). $$
%K Neutral equation
%K positive periodic solution
%U http://ejde.math.txstate.edu/Volumes/2012/14/abstr.html