1. Baldwin, R. A.: 1963,The Measure of the Moon, Univ. of Chicago Press, 488 pp.
2. Beals, C. S., Innes, M. J. S., and Rottenberg, J. A.: 1963, in B. Middlehurst and G. Kuiper (eds.),The Solar System, v. 4, The Moon, Meteorites and Comets, Univ. Chicago Press, pp. 235?282.
3. Carr, M. H., Crumpler, L. S., Cutts, J. A., Greeley, R., Guest, J. E., and Masursky, H.: 1977,J. Geophys. Res. 82, 4055?4065.
4. Cintala, M. J.: 1979,Proc. 10th Lunar Planet. Conf. 2635?2650.
5. Fredriksson, K., Dube, A., Milton, D. J. and Balasundarum, M. S.: 1973,Science 180, 862?864.