Asymptotic properties of even-order functional differential equations with deviating argument.

In this paper, new effective technique for investigation of the higher order differential equation (E) y(n)(t) = p(t)y(τ(t)). is established. We offer new criteria for excluding certain types of nonoscillatory solutions which improve all existing results from the literature. Examples are provided to illustrate the importance of the main results. [ABSTRACT FROM AUTHOR]