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2. An algorithm for computing Lyapunov functionals for some differential-difference equations;Datko,1971
3. Introduction to Functional Differential Equations;Hale,1993
4. Generalization of Lyapunov’s theorem in a linear delay system;Huang;Journal of Mathematical Analysis Applications,1989
5. A Lyapunov functional for a matrix difference-differential equation;Infante;Journal of Differential Equations,1978