1. Friedman, Sy D., An Introduction to β-Recursion Theory, this volume.
2. Friedman, Sy D., β-Recursion Theory, to appear.
3. Friedman, Sy D., Post's Problem without Admissibility, to appear.
4. Friedman, Sy D., Negative Solutions to Post's Problem, II, in preparation.
5. Prikry, Karel, On a Theorem of Silver, handwritten notes