1. Baxter, D., and Thompson, W. B., Proc. Twelfth Coll., IAU, Tucson (March 1971).
2. Baxter, D., and Thompson, W. B., Astrophys. J. (in the press).
3. Verniani, F., Smithsonian Contrib. Astrophys., 10, 181 (1967).
4. Kresak, L., IAU Symposium 33, Physics and Dynamics of Meteors (Springer-Verlag, New York, 1968).
5. Mendis, D. A., Astrophys. Space Sci., 20, 165 (1973).