Oscillation of second order functional differential equations with damping

Using a class of new test functions Φ(t, s, r) defined in our recent work [Y.G. Sun, New Kamenev-type oscillation criteria for second order nonlinear differential equations with damping, J. Math. Anal. Appl. 291 (2004) 341–351], we establish some new oscillation criteria for the second order functional differential equation with dampingx″(t)+p(t)x′(t)+∫abq(t,ξ)fx[g1(t,ξ)],…,x[gm(t,ξ)]dσ(ξ)=0.Our results are different from most known ones and can be applied to many cases which are not covered by existing results.