1. Bigg, E. K., Astron. J., 72, 463 (1967).
2. Lamb, Horace, Hydrodynamics, 359 (Cambridge Univ. Press, 1932).
3. H.M. Nautical Almanac Office, Planetary Coordinates (1933, 1958).
4. Tuckerman, B., Planetary, Lunar, and Solar Positions, AD 2 to AD 1649 (Phil. Soc. Amer., 1964).
5. Waldmeier, M., The Sunspot-Activity in the Years 1610–1960 (Technische Hochschule, Zurich, 1961).