1. Oscillation Theory of Differential equations with Deviating Arguments;Ladde,1987
2. Stability and Oscillation in Delay Differential Equation of Population Dynamics;Gopalsamy,1992
3. Oscillation Theory for Functional Differential Equations;Erbe,1995
4. Oscillation Theory of Delay Differential Equation with Applications;Györi,1991
5. Ordinary Differential Equations;Hartman,1982