1. Parkinson, R. W., H. M. Jones, and I.I. Shapiro: Science 181, 920 (1960).
2. See, for example, F. R. Moulton: Celestial Mechanics (New York: Mac-millan Co., 1914).
3. Shapiro, I.I., and H.M.Jones: J. Geophys. Res. 66, 4123 (1961).
4. The major architect of this program was H. M. Jones. Other contributors include C. W. Perkins, P. Willmann, M. Ash, and C. Berger. G. Strang, with the help of P. Willmann, also constructed a triple-precision Runge-Kutta integration program which includes the effects of the earth’s gravitational potential, direct sunlight pressure, and air drag, simulated by a simple model. This latter has been very useful for checking purposes.
5. King-Hele, D. G.: Geophys. J. 4, 3 (1961).