1. Birkhoff, G., Hydrodynamics, revised ed. Princeton University Press, Princeton, N. J., 1960, pp.115-116.
2. Mason, M. et al. "Underpressure at Separation Area and Theory of Venting," in "Water Entry and Underwater Ballistics of Projectiles," Rept. 2551,1946, Office of Scientific Research and Development,California Institute of Technology, Pasadena, Calif., pp.45-78.