1. Hann, J. (1883) Handbuch der Klimatologie. J. Engelhorn, Stuttgart.
2. Hann, J. and Ward, R.D.C. (1903) Handbook of Climatology. Macmillan, New York.
3. Bretagnon, P. (1974) Termes a longues periodes dans le systeme solaire. Astronomy & Astrophysics, 30, 141-154.
4. Milankovitch Theory and climate