1. Linear Differential Equations with Retarded Argument;Myshkis,1972
2. Differential Equations of the Second Order with Retarded Argument;Norkin,1972
3. Oscillation Theory of Differential Equations with Deviating Argument;Ladde,1987
4. Oscillation Theory of Delay Differential Equations;Györi,1991
5. Oscillation Theory for Functional Differential Equations;Erbe,1995