1. Bjorkholm, P. J., Golub, L., and Gorenstein, P.: 1973,Proc. Fourth Lunar Science Conf., Geochim. Cosmochim. Acta, Suppl. 4,3, 2793?2802.
2. Burnett, D. S. and Woolum, D. S.: 1974,Proc. Fifth Lunar Science Conf., Geochim. Cosmochim. Acta, Suppl. 5,2, 2061?2074.
3. Criswell, D. R.: 1972,Proc. Third Lunar Science Conf., Geochim. Cosmochim. Acta, Suppl. 3,3, 2671?2680.
4. Fastie, W. G., Feldman, P. D., Henry, R. C., Moos, H. W., Barth, C. A., Thomas, G. E., and Donahue, T. M.: 1973,Science 182, 710?711.
5. Ganapathy, R. and Anders, E.: 1974,Proc. Fifth Lunar Science Conf., Geochim. Cosmochim. Acta, Suppl. 5,2, 1181?1206.