1. Ajzerman, M.A. and Gantmacher, F.R. (1964). Absolute Stability of Regulator Systems. Holden-Day, San Fran cisco.
2. Arcak, M., Larsen, M. and Kokotovic, P. (2003). Circle and Popov criteria as tools for nonlinear feedback design. Automatica, vol. 39, no. 4, pp. 643–650.
3. Fomin, V.N., Fradkov, A.L. and Yakubovich, V.A. (1981). Adaptive control of dynamic objects. Nauka, Moscow. (in Russian).
4. Fradkov, A.L. (1974). Synthesis of an adaptive system for linear plant stabilization. Autom. Remote Control, vol. 35 no. 12, pp. 1960–1966.
5. Fradkov, A.L. (1976). Quadratic Lyapunov functions in the adaptive stabilization problem of a linear dynamic plant. Siberian Math. J., no. 2, pp. 341–348.