1. Linear Optimal Control Systems;Kwakernaak,1972
2. Proportional minus delay controller;Suh;IEEE Trans. Aut. Contr.,1979
3. Use of time-delay actions in the controller design;Suh;IEEE Trans. Aut. Contr.,1980
4. Applied Theory of Functional Differential Equations;Kolmanovskii,1992
5. Van der Pol's oscillator under delayed feedback;Atay;J. Sound Vib.,1998