Oscillatory properties of solutions of three-dimensional differential systems of neutral type

summary:The purpose of this paper is to obtain oscillation criteria for the differential system \[ \begin{aligned}{[y_1(t)-a(t)y_1(g(t))]}^{\prime}&=p_1(t)f_1(y_2(h_2(t))) \\ y_2^{\prime }(t)&=p_2(t)f_2(y_3(h_3(t))) \\ y_3^{\prime }(t)&= - p_3(t)f_3(y_1(h_1(t))), \quad t\in \mathbb R_+=[0,\infty ).\end{aligned} \