1. Optimal Control of Distributed Parameter Systems;Ahmed,1981
2. Equations paraboliques à retardement;Artola;C. R. Acad. Sci. Paris,1967
3. Optimal control problems in Banach spaces;Balakrishnan;SIAM J. Control,1965
4. Applied Functional Analysis;Balakrishnan,1981
5. Necessary conditions for control problems with variable time-lags;Banks;SIAM J. Control,1969