References
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- Györi , I. 1991 . “ Oscilation Theory of Delay Differential Equations with Applications ” . Oxford : Clarendon Press .
- Chuanaxi , Q. and Ladas , G. 1991 . " Linearized oscillations for even-order neutral differential Equations " . J. Math. Anal. Appl , 159 : 237 – 250 .
- Ladas , G. 1989 . " Linearized oscillations for neutral equation, in proceedings of Equadiff 87 Leture Notes in pure and Applied Mathematics ” . In Differential Equations , Vol. 118 , 378 – 379 . Marcel Dekker Inc .