1. Stability of Motion;Krasovskii,1963
2. The application of Lyapunov's method to problems in the stability of systems with delay;Razumikhin;Automat. Remote Control,1960
3. Stability of Motion for Dynamic Systems with Time Delay;Qin,1963
4. Differential and Integral Inequalities: Theory and Applications;Lakshmikantham,1969
5. Theory of Functional Differential Equations;Hale,1977