1. Barwise, J., Admissible sets and structures, Springer Verlag.
2. Burgess, J., Infinitary languages and descriptive set theory, Ph.D. thesis, Berkeley, 1974.
3. Burgess, J., Equivalences generated by families of Borel sets, to appear in Proc. AMS.
4. Burgess, J., Effective enumeration of classes in a σ 1 1 equivalence relation, to appear.
5. Friedman, H., Countable models of set theories, in: Cambridge Summer School in Mathematical Logic, ed. by A.R.D. Mathias and H. Rogers, Springer Lecture Notes No. 337.