On the oscillation of certain second-order nonlinear differential equations

In this paper, oscillation criteria for the nonlinear second-order ordinary differential equation r(t)Ψ x(t) x (t ) p−2 x (t ) + c(t )f x(t) = 0 are given. The results extend the integral averaging technique and include earlier results. Our methodology is somewhat different from that of previous authors.  2003 Elsevier Science (USA). All rights reserved.