1. “Stability of recursive structures in arithmetical degrees”;Ash;Annals of Pure and Applied Logic,1986
2. “Categoricity in hyperarithmetical degrees”;Ash;Annals of Pure and Applied Logic,1987
3. “Recursive labelling systems and stability of recursive structures in hyperarithmetical degrees”;Ash;Trans. of the Amer. Math. Soc.,1986
4. “Labelling systems and r.e. structures”;Ash;Annals of Pure and Applied Logic,1990
5. “A construction for recursive linear orderings”;Ash;J. Symb. Logic,1990