1. Caputo, M., 1967. The Gravity Field of the Earth. From Classical and Modern Methods. Academic Press, New York, London.
2. The Mathematics of Projectiles in Sport;de Mestre,1990
3. Analysis of the trajectory of the shot;Garfoot;Track Technique,1968
4. Biomechanics of Sports Techniques;Hay,1985
5. The Earth's gravity;Heiskanen;Scientific American,1955