1. Bodley, C. S., Devers, A. D., Park, A. C., Frisch, H. P. (1978), DISCOS, I, II, Nasa Technical Paper 1219.
2. Imbert, J. F. (1979);Analyse des structures par �l�ments finis, Paris.
3. Hugues, P. C., (1974),Celest. Mech.,9, 21?39.
4. Likins, P. W., Barbera, F. J., Baddeley, V., (1973),A.I.A.A.J.,11, 9, 1251?1258.
5. Linkins, P. W., Ohkami, Y., Chung Wong, (1976),A.I.A.A.J.,13, 10, 611?617.