1. Jacchia, L. G., Harvard Announcement Card 1391 (Feb. 5, 1958).
2. Jacchia, L. G., Smithsonian Obs. Spec. Report No. 13 (May 21, 1958).
3. Jacchia, L. G., and Briggs, R. E., Smithsonian Obs. Spec. Report No. 18 (Oct. 4, 1958).
4. Cornford, E. C., R.A.E. Report (July 1958).
5. King-Hele, D. G., Nature, 182, 1409 (1958).