Erratum to: "Oscillation of forced neutral differential equations with positive and negative coefficients" [Comput. Math. Appl 54 (2007) 1411-1421]

In [1], the author studied the oscillation of forced neutral delay differential equations with positive and negative coefficients, having the following form: [x(t)− R(t)x(t − r)] + P(t)x(t − τ)− Q(t)x(t − σ) = f (t), (1) where R, P, Q ∈ C([t0,∞),R) with r > 0, τ ≥ σ ≥ 0. The readers are referred to [1] for further details. The author uses an ill representation which yields a mistake. To avoid the mistake, we introduce the following representations: