| [ref.33] | Miller, S. L.: Production of Some Organic Compounds Under Possible Primitive Earth Conditions. J. Am. Chem. Soc., vol. 77, 1955, p. 235. |
| [ref.34] | Oró, J.: Experimental Cosmochemistry. In Current Aspects of Exobiology. G. Mamikunian and M. H. Briggs, eds., Pergamon Press (New York), 1965. |
| [ref.35] | Shapley, H.: Of Stars and Men. Beacon Press (Boston), 1958, pp. 11 and 157. |
| [ref.36] | Lederberg, J.; and Cowie, D. B.: Moondust. Science, vol. 127, 1958, pp. 1473-1475. |
| [ref.37] | CETEX: Development of International Efforts To Avoid Contamination by Extraterrestrial Exploration. Science, vol. 128, 1958, pp. 887-889. |
| [ref.38] | CETEX: Contamination by Extraterrestrial Exploration. Nature, vol. 183, 1959, pp. 925-928. |
| [ref.39] | Sagan, C.: Biological Contamination of the Moon. Proc. Natl. Acad. Sci. U.S., vol. 46, 1960, pp. 393-401. |
| [ref.40] | Davies, R. W.; and Communizis, M. G.: Sterilization of Space Vehicles To Prevent Extraterrestrial Biological Contamination. Proc. 10th Intern. Astro. Congr., Springer-Verlag (Vienna), 1960, pp. 495-504. |
| [ref.41] | Lederberg, J.: Exobiology: Approaches to Life Beyond the Earth. Science, vol. 132, 1960, pp. 393-400. |
| [ref.42] | Brown, A. H.: Report of the Working Subgroup on Space Probe Sterilization. A Review of Space Research. Natl. Acad. Sci.-Natl. Res. Council, Publ. 1079, 1962, ch. 10. |