On the oscillation of certain functional differential equations via comparison methods

Several new criteria for the oscillation of the functional differential equations of the form d dt 1 an−1(t ) d dt 1 an−2(t ) d dt ··· 1 a1(t ) d dt x(t) α ± q(t)f x g(t) = 0 are established in this paper.  2003 Elsevier Inc. All rights reserved