1. I. Prigogine, A. Grecos, and Cl. George,Celest. Mech. 16, 489 (1977).
2. T. Y. Petrosky,Phys. Rev. A 32, 3716 (1985).
3. A. N. Kolmogorov, inFoundations of Mechanics, R. Abraham, ed. (W. A. Benjamin, New York, 1967), Appendix D.
4. V. I. Arnold,Russ. Math. Surv. 18, 9 (1963);18, 85 (1963).
5. J. Moser,Nachr. Akad. Wiss. Göttingen II, Math. Phys. Kl. 1, 1 (1962).