Oscillation of nonlinear neutral delay differential equations of second-order with positive and negative coefficients

Some oscillation criteria for the following second-order neutral differential equation [x(t) +/- r(t)f(x(t - gamma))]'' + p(t)g(x(t - alpha)) - q(T)g(x(t - beta)) = s(t) where t >= t(0), gamma, alpha, beta is an element of R+ with alpha >= beta, r is an element of C-2([t(0), infinity), R+), p, q is an element of C([t(0), infinity), R+) and f, g is an element of C(R, P.), s is an element of C([t(0), infinity), R) have been obtained. Our results are not restricted with boundedness of soultions.