1. Bell, J. F., Davis, D. R., Hartmann, W. K. & Gaffey, M. J. 1989, in Asteroids II, ed. R. P. Binzel, T. Gehrels, & M. S. Matthews (Tucson: Univ. Arizona Press), 921
2. Bell, J. F., Owensby, P. D., Hawke, B. R. & Gaffey, M. J. 1988, in Lunar and Planetary Science XIX (Houston: Lunar Planet. Inst.), 57
3. Bowell, T. & Lumme, K. 1979, in Asteroids, ed. T. Gehrels (Tucson: Univ. Arizona Press), 132
4. Britt, D. & Pieters, C. 1988, in Proc. 18th Lunar and Planetary Science Conference, ed. G. Ryder (Cambridge: Cambridge Univ. Press), 503
5. Bus, S. J. 1999, Ph.D. thesis, MIT