1. BERNETT, E.C., AIAA JOURNAL 2: 94 (1964).
2. CAMPBELL, M.J., DENSITY OF LUNAR SURFACE, SCIENCE 159: 973 (1968).
3. CHERKASOV, I.I., COSMIC RESEARCH 5: 636 (1967).
4. CHERKASOV, I.I., KOSMICHESKIYE ISSLEDOVANIYA 5: 746 (1967).
5. Cherkasov, I. I., Proceedings of the Geotechnical Conference Oslo 1: 179 (1967).