J. Dzurina, OSCILLATION OF 2ND-ORDER DIFFERENTIAL-EQUATIONS WITH MIXED ARGUMENT, Journal of mathematical analysis and applications, 190(3), 1995, pp. 821-828
Our aim in this paper is to present a sufficient condition for the osc
illation of the second order differential equation with mixed argument
(1/r(t) u'(t))' + p(t)u(tau(t)) + q(t)u(sigma(t)) = 0. () We compare
() with the first order advanced equation of the form z'(t) - q(2)(t
)z(sigma(t)) = 0. (C) 1995 Academic Press, Inc.