Bulk density of asteroid 243 Ida from the orbit of its satellite Dactyl - Belton, M.; Chapman, C.; Thomas, P.C.; Davies, M.; Greenberg, R.; Klaasen, K.; Byrnes, D.; D’Amario, L.; Synnott, S.; Johnson, T.; McEwen, A.; Merline, W.J.; et al. (Nature, 1995)