1. Intrinsically recursive relations;Ash,1981
2. Ramified systems;Ash;Ann. Pure Appl. Logic,1994
3. C.J. Ash and J.F. Knight, Mixed, ramified permitting systems, in preparation.
4. Some effects of Ash-Nerode and other decidability conditions on degree spectra;Harizanov;Ann. Pure Appl. Logic,1991
5. Degrees of Unsolvability;Sacks,1963