Oscillation for difference equations with continuous variable

Consider the delay difference equation y(t) − y(t−τ) + p(t)H(y(t − θ)) = ƒ(t), t 0, where τ > 0, σ > 0, and p ε C(R+, R+), f ε C(R+, R), H ε C(R, R). Some oscillation criteria for this equation are obtained.