Existence and asymptotic behavior of solutions of nonlinear neutral differential equations

The nonlinear neutral differential equation equation(1)dndtn[x(t)+h(t)x(τ(t))]+f(t,x(g(t)))=q(t), is considered under the following conditions: n∈N; h∈C[t0,∞)h∈C[t0,∞); τ∈C[t0,∞)τ∈C[t0,∞) is strictly increasing, limt→∞τ(t)=∞limt→∞τ(t)=∞ and τ(t)