1. Anosov, D. V.: Averaging in systems of ordinary differential equations with rapidly oscillating solutions. Izv. Akad. Nauk SSSR, Ser. Mat. 24, 721-742 (1960) (Russian)
2. Arnold, V. I.: Small denominators and problems of stability of motion in classical and celestial mechanics. Russ. Math. Surv. 18, No. 6, 85-191 (1963)
3. Arnold, V. I.: Conditions for the applicability, and estimate of the error, of an averaging method for systems which pass through states of resonance in the course of their evolution. Sov. Math., Dokl. 6, 331-334 (1965)
4. Arnold, V. I.: Mathematical Methods of Classical Mechanics. Springer, New York (1978)
5. Arnold, V. I.: Geometrical Methods in the Theory of Ordinary Differential Equations. Springer, New York (1988)