3Cui Baotong,Li Weinian.A necessary and sufficient condition for oscillation of parabolic equations with several delays. Journal of Computational and Applied Mathematics .
4Mishev D. P. and Bainov D. D.Oscillation of solutions of parabolic differential equations of neutral type, Appl. Mathematics of Computation . 1988
5Mishev D. P. and Bainov D. D.A necessary and sufficient condition for oscillaion of neutral type hyperbolic equations,J. Computational and Applied Mathematics . 1992
6Jiang Ziwen.Oscillation of first order neutral delay differential equations,J.Math. Anal. Appl . 1995
7Lalli B. S.Yu Yuanhong and Cui Baotong.Oscillations of hyperbolic equations with functionul arguments, Appl. Mathematics of Computation . 1993
8Cui Baotong.Oscillation properties of the solations of hgperbolic equations with deviating arguments. Demonstratio Mathematica . 1996
