Oscillation criteria for nth order nonlinear neutral differential equations

Sufficient conditions are established for the oscillation of nth order neutral differential equations of the formr(t)x(t)|x(t)|α-1+p(t)x(τ(t))(n-1)′+q(t)fx(σ(t))=0,t⩾t0,where n⩾2 is even integer, α⩾1,p,q∈C([t0,+∞),R),f∈C(R,R). The results obtained extend some of the known results.