References
- Grammatikopoulos , M.K. , E. A. , Grove and G. , Ladas . 1986 . Oscillation and asymptotic behavior of second order neutral differential equations with deviating arguments . Proceedings of the Inter* national Conference in Differential Equations, Univ, of Toronto , : 14 – 26 .
- Ladas , G. , Partheniadis , E.G. and Sficas , Y, G. 1986 . Oscillations of second order neutral equations .
- Ladas , G. , Sficas , Y. G. and Stavroulakis , I. P. 1984 . Necessary and sufficient conditions for oscillations of higher order delay differential equations . Trans, A,M.S , 285 : 81 – 90 .