Abstract
In this work, we prove some new oscillation theorems for second-order neutral delay differential equations of the form (a(xi)((v(xi)+b(xi)v(theta(xi)))'))'+c(xi)G(1)(v(kappa(xi)))+d(xi)G(2)(v(zeta(xi)))=0 under canonical and non-canonical operators, that is, integral(infinity)(xi 0)d xi/a(xi) = infinity and integral(infinity)(xi 0)d xi/a(xi) < infinity. We use the Riccati transformation to prove our main results. Furthermore, some examples are provided to show the effectiveness and feasibility of the main results.