1. A. I. Lur’e and V. N. Postnikov, “On the theory of stability of control systems,” Applied Mathematics and Mechanics (in Russian), vol. 8, no. 3, pp. 246–248, 1944.
2. Q. C. Zhong, Robust Control of Time-delay Systems, Springer, 2006.
3. K. Gu, V. L. Kharitonov, and J. Chen, Stability of Time-delay Systems, Birkhauser, 2003.
4. J. E. Normey-Rico and E. F. Camacho, Control of Dead-time Processes, Springer, 2007.
5. N. N. Krasovskii, Stability of Motion, (translation by J. Brenner), Stanford University Press, Stanford CA, USA, 1963.