1. Barth, C. A.: 1968, J.Atmospheric Sci. 25, 564.
2. Barth, C. A.: 1974, Ann. Rev. Astron. Astrophys., to be published.
3. Barth, C. A. and Leovy, C. B.: 1974, private communication.
4. Barth, C. A., Pearce, J. B., Kelly, K. K., Wallace, L., and Fastie, W. G.: 1967, Science 158, 1675.
5. Bauer, S. J. and Hartle, R. E.: 1974, Geophys. Res. Letters 1, 7.