1. A. M. LIAPUNOV, “Probléme général de la stabilité du mouvement,” pp. 1907–1949 (Ann. Math. Studies, Vol. 9). Princeton Univ. Press, Princeton, New Jersey.
2. “Theorie und Anwendung der Direkten Methode von Liapunov.”;HAHN,1959
3. Control system analysis and design via the “second method” of Liapunov: Pt. 1, Continuous-time systems;KALMAN;ASME Trans. J. Basic Eng.,1960
4. R. E. KALMAN and J. E. BERTRAM, Control system analysis and design via the “second method” of Liapunov. Pt. 2, Discrete-time systems. ASME Trans. J. Basic Eng. No. 59-NAC-3 [see ref. (3)].
5. “Stability in Nonlinear Control Systems.”;LETOV,1961