1. Poincare, H., Les Méthodes Nouvelles de la Mécanique Céleste, Gauthier-Villars, Paris, 1889.
2. Birkhoff, G.D., Dynamical Systems, AMS. Collection Publications, vol.9, reprinted 1966.
3. Amold, V.I., Mathematical Methods of Classical Mechanics, Springer, New-York Heidelberg Berlin,1978.
4. Moser J., Stable and Random Motion in Dynamical Systems, Hermann Weyl Lectures, Princeton, New-Jersey, 1973.
5. Brjuno, A.D., Analytical forms of Differential Equations I, Transactions of the Moscow Mathematical Society, 25, pp.132–198, 1971.