1. N. N. Bogolyubov and Yu. A. Mitropol'skii, ?The method of integral manifolds in nonlinear mechanics,? Proc. Int. Symp. on Nonlinear Oscillations [in Russian], Vol. 1, Izd. Akad. Nauk Ukr.SSR, Kiev (1963), pp. 93?154.
2. Yu. A. Mitropol'skii and O. B. Lykova, Integral Manifolds in Nonlinear Mechanics, Nauka, Moscow (1973).
3. A. B. Vasil'eva and V. F. Butuzov, Asymptotic Expansions of Solutions of Singularly Perturbed Equations [in Russian], Nauka, Moscow (1973).
4. V. V. Strygin and V. A. Sobolev, ?The influence of geometric and kinetic parameters and dissipation of energy on the stability of orientation of satellites with double rotation,? Kosm. Issled.,14, No. 3, 366?371 (1976).
5. V. A. Sobolev and V. V. Strygin, ?On the admissibility of transition to processional equations of gyroscopic systems,? Izv. Akad. Nauk SSSR, Mekh. Tverd. Tela, No. 5, 10?17 (1978).