1. Alexander, A. F .O’D.: 1962, The Planet Saturn, London.
2. Blanco, V. M. and McCuskey, S. W.: 1961, Basic Physics of the Solar System, Reading, Mass.
3. Gingerich, O.: 1964, Sky and Telescope
28, 278. Describes the same exercise.
4. Giver
L. P., : 1963, Astrophys. J.
139, 727.
5. Sharonov, V. V.: 1964, The Nature of the Planets, Jerusalem, p. 68 (From the Russian).