1. Distribution of Density in a Planetary Exosphere
2. S. Chapman and T. G. Cowling,The Mathematical Theory of Non-Uniform Gases(Cambridge University Press, New York, 1939), p. 69.
3. L. Spitzer,The Atmospheres of the Earth and Planets, edited by G. P. Kuiper (University of Chicago Press, Chicago, Illinois, 1952), p. 223.
4. J. W. Dungey, inThe Physics of the Ionosphere(The Physical Society, London, England), p. 229.
5. F. S. Johnson and R. A. Fish, Astrophys. J. (in press).