1. West, R. M., Laubetts, A., J0rgensen, H. E. & Schuster, H. E. Astr. Astrophys. (submitted). 2. White, G. L. & Malin, D. F. IAU Ore. No. 4330 (1987);
2. Nature 327, 36???38 (1987). 3. Hirata, et al. Phys Rev. Lett, (submitted). 4. Sonneborn, G. & Kirshner, R. IAU Circ. No. 433 (1987). 5. Panagia, W. et al. Astr. Astrophys. (in the press). 6. Brunish, W. E. & Truran, J. W. Astrophys. J. Suppl. Ser. 49, 447???468 (1982). 7. Kippenhahn, R., Weigert, A. & Hofmeister, E. in Methods in Computational Physics, Vol. 7 (eds Alder, B., Fernbach, S. & Rotenberg, M.) 129???190 (Academic, New York, 1967). 8. Weiss, A. Astr. Astrophys. (in the press). 9. Hiibner, W. F., Merts, H. L., Magee, N. H. Jr & Argo, M. F. Los Alamos Sci. Lab. Rep. LA 6760 M (1977). 10. Chiosi, C. & Maeder, A. A Rev. Astr. Astrophys. 24, 329???375 (1987). 11. Falk, S. W. & Arnett, W. D. Astrophys. J. Suppl. Ser. 33, 515???562 (1977). 12. Sedov, L. I. Similarity and Dimensional Methods in Mechanics 260 (Academic, New York, 1959). 13. Wilson, J. R., Mayle, R., Woosley, S. E. & Weaver, T. Ann. N. Y. Acad. Sci. (in the press). 14. Woosley, S. A. & Weaver, T. A. A. Rev. Astr. Astrophys. 24, 205???293 (1986). 15. Thielemann, F. K. & Arnett, W. D. Astrophys. J. 295, 604???619 (1985).