Oscillation criteria for second-order retarded differential equations

Some oscillation criteria for the second order retarded differential equation [r(t)¦u′(t)¦α−1 u′(t)]′ + p(t)¦u(τ(t))¦β−1u(τ(t)) = 0 are given, where α and β are positive constants, and p, τ, r ϵ C([t0,∞), R satisfy some suitable conditions. Our results generalize those of Erbe, Ohriska and Lakshmikatham.