MB Mesmouli, A Ardjouni, A Djoudi - Boletín de la Sociedad Matemática …, 2016 - infona.pl
In this paper, we study the existence of periodic solutions of the nonlinear neutral system of
differential equations $$\begin {aligned}\frac {\mathrm {d}}{\mathrm {d} t} x\left (t\right)= A\left …