Green's function for second order differential equations with piecewise constant arguments

In this paper, the second order nonautonomous differential equations with piecewise constant argumentsx″(t)+(α(t)-β(t))x′(t)-(β′(t)+α(t)β(t))x(t)+c(t)x′([t])+d(t)x([t])=σ(t),t∈[0,T],x(0)=x(T),x′(0)=x′(T)+λis considered. We obtain the Green's function to express the unique solution for the system.