1. Becker, S.A. and Iben, I. 1979, Ap.J., 232, 831.
2. Bedijn, P.J. 1986, preprint.
3. Bertschinger, E. and Chevalier, R.A. 1985, Ap.J., 299, 167.
4. Bessell, M.S., Freeman, K.C. and Wood, P.R. 1986, Ap.J., in press.
5. Bowen, G.H. and Beach, T.E. 1986, in Workshop on the Late Stages of Stellar Evolution, eds. S. Kwok and S. Pottasch (Dordrecht: Reidel), in press.