1. L. Collatz, Functional Analysis and Numerical Mathematics, Academic Press, New York (1966).
2. A. A. Martynyuk and A. S. Khoroshun, “The theory of parametric stability revisited,” Dop. NAN Ukrainy, No. 7, 59–65 (2007).
3. Yu. A. Mitropolsky and O. B. Lykova, Integral Manifolds in Nonlinear Mechanics [in Russian], Nauka, Moscow (1954).
4. Yu. I. Neimark and N. A. Fufaev, Dynamics of Nonholonomic Systems [in Russian], Nauka, Moscow (1967).
5. M. Ikeda, Y. Ohta, and D. D. Siljak, “Parametric stability,” in: Proc. Joint Conf. of Univesita di Genova and Ohio State University, Birkhauser, Basel (1991), pp. 1–12.