1. Hoyle, F., Fowler, W. A., Burbidge, G. R., and Burbidge, E. M., Astrophys. J., 139, 909 (1964).
2. Chiu, H.-Y., Quasi-Stellar Sources and Gravitational Collapse (edit. by Robinson, I., Schild, A., and Schucking, E. L.) (University of Chicago Press, Chicago, 1965).
3. Fowler, W. A., and Hoyle, F., Nucleosynthesis in Massive Stars and Supernovae (University of Chicago Press, Chicago, 1964).
4. Rakavy, G., Shaviv, G., and Zinamon, Z., Astrophys. J., 150, 131 (1967). Arnett, W. D., Supernovae Conf., New York, November 1967 (in the press).
5. Colgate, S. A., and White, R., Astrophys. J., 143, 626 (1966).