1. Cann, M. W. P., Davies, W. O., Greenspan, J. A., and Owen, T. C.: 1965, NASA CR-298 Technical Report, IIT Research Institute.
2. Coulson, K. L.: 1969, Appl. Opt. 8, 1287.
3. de Vaucouleurs, G.: 1964, Icarus 3, 187.
4. Dollfus, A.: 1966, Compt. Rend. Acad. Soc. Paris 262, Serie b, 519.
5. Dollfus, A. and Focas, J. H.: 1966, Polarimetric Study of the Planet Mars (AFCRL 66–492 (AD635, 928), Air Force Cambridge Research Laboratories, through European Office of Aerospace Research).