Oscillation of neutral differential equation with positive and negative coefficients

In this paper, we provide oscillation properties of every solution of the neutral differential equation with positive and negative coefficients[x(t)−R(t)x(t−r)]′+P(t)x(t−τ)−Q(t)x(t−σ)=0,[x(t)−R(t)x(t−r)]′+P(t)x(t−τ)−Q(t)x(t−σ)=0, where R(t),P(t),Q(t)∈C([t0,∞),R+)R(t),P(t),Q(t)∈C([t0,∞),R+), r>0r>0, τ⩾0τ⩾0, σ⩾0σ⩾0.