1. Robinson, Schild, and Schuecking (editors), Quasi Stellar Radiosources and Gravitational Collapse (University of Chicago Press, 1964).
2. Proc. Second Texas Symp. Relativistic Astrophys. (December 1964) (to be published).
3. Gratton, L., edit. by, Proc. Varenna Summer School on High Energy Astrophys.(July 1965) (to be published).
4. Harrison, B. K., Thorne, K. S., Wakano, M., and Wheeler, J. A., Gravitation Theory and Gravitational Collapse (University of Chicago Press, 1965).
5. Fowler, W., in Padua Symp. Cosmology (September 1964) (to be published).