1. B. P. Demidovich, Lectures on the Mathematical Theory of Stability (Nauka, Moscow, 1967) [in Russian].
2. D. L. Lukes, Differential Equations: Classical to Controlled (Academic, New York, 1982).
3. C. J. Harris and J. F. Miles, Stability of Linear Systems (Academic, London, 1980).
4. V. M. Morozov and V. I. Kalenova, Estimation and Control in Time-Varying Linear Systems (Mosk. Gos. Univ., Moscow, 1988) [in Russian].
5. V. M. Morozov and V. I. Kalenova, “Application of the Methods of Reducibility to Dynamic Problems of Gyroscopic Systems,” Izv. Akad. Nauk SSSR, Mekh. Tverd. Tela, No. 1, 8–14 (1987) [Mech. Solids 22 (1), 6–12 (1987)].