1. Arnold, V. I.: Small Divisors I, On mappings of a circle onto itself. Izvest. Akad. Nauk., Ser. Mat.25, No. 1, 21?86 (1961).
2. ?? Proof ofA. N. Kolmogorov's theorem on the preservation of quasi-periodic motions under small perturbations of the Hamiltonian. Uspekhi Mat. Nauk U.S.S.R.18, Ser. 5 (113), 13?40 (1963).
3. Charlier, C. L.: Die Mechanik des Himmels. Vol.2, Section 10, § 5, § 6. Leipzig 1907.
4. Jacobson, N.: Lie Algebras. New York-London: Interscience 1962.
5. Kolmogorov, A. N.: Doklady Akad. Nauk U.S.S.R.98, 527?530 (1954).