Oscillation of second-order nonlinear neutral differential equations ✩

In this paper, some sufficient conditions for oscillation and nonoscillation are obtained for the second-order nonlinear neutral differential equation x(t) − p(t)x(t − τ) +q(t)f x(t − σ) = 0, t 0, (∗) where 0 p(t) 1, q(t) 0, τ,σ >0.  2004 Elsevier Inc. All rights reserved.