Oscillation of even order delay differential equations (Q1097393)

The authors found some oscillation criteria fpr the even order functional differential equations: \[ x^{(n)}(t)+q(t)f(x(t),x(g_ 1(t)),...,x(g_ m(t)))=0 \] and \[ x^{(n)}(t)+p(t)x^{(n- 1)}(t)+q(t)f(x(g_ 1(t)),...,x(g_ m(t)))=0. \]