1. Anders, E. and Ebihara, M. 1982 Geochim. Cosmochim. Acta 46, 2363.
2. Bartel, N., Ratner, M.I., Rogers, A.E.E., Shapiro, I.I,, Bonometti, R.J., Cohen, N.L., Gorenstein, M.V., Marcaide, J.M., and Preston, P.A. 1987 Ap.J. 323, 505.
3. Binns, W.R., Garrard, T.L., Israel, M.H., Klarmann, J., Stone, E.L. and Waddington, C.J., 1989 in “Cosmic Abundances of Matter” ed. C.J. Waddington (New York: AIP Conf. Proc. 185), p. 147.
4. Burnett, T.H., et al. 1989 Cosmic Abundances of Matter, ed. C.J. Waddington, (New York: AIP Conf. Proc. 183), p. 396.
5. Burnett, T.H. et al. 1990 Ap. J. (Letters), 349, L25.