1. Newton, Sir I., Principia (Mathematical Principles of Natural Philosophy}, Bk. II, translated by A. Motte, translation revised by F. Cajori, University of California Press, Berkeley, Calif. 1946, pp.352-366.
2. Eiffel, G. "Sur la resistance des Spheres dans 1'air en mouvement," Academic des Sciences, Comptes Rendus, Vol.155, 1912, pp.1597-1599.
3. IX. Theory of the measurement of wind by shooting spheres upward
4. LXXV. Experiments on the resistance of the air to falling spheres