1. Abraham, R., 1967, “Foundations of Mechanics”, W. A. Benjamin, Inc., Philadelphia.
2. Andoyer, H., 1926, “Cours de Mécanique Célèste”, (Vol. I), Gauthier-Villars, Paris.
3. Arnol’d, V. I., 1963, “Proof of A. N. Kolmogorov’s Theorem on the Conservation of Quasiperiodic Motions under Small Perturbations of the Hamiltonian”, Uspekhi Mat. Nauk USSR, 18, 13–40.
4. Arnol’d, V. I., 1963? “Small Denominators and Problems of Stability of Motion in Classical and Celestial Mechanics”, Uspekhi Mat. Nauk USSR, 18, 91–192.
5. Intern. Astrom. Union Symp.;B Barbanis,1966