Pseudo-Complements and Ordinal Logics based on Consistency Statements. - Robert A. Di Paola (J. Symb. Log., 1966)

Some Theorems on Extensions of Arithmetic. - Robert A. Di Paola (J. Symb. Log., 1967)

The Recursive Unsolvability of the Decision Problem for the Class of Definite Formulas. - Robert A. Di Paola (J. ACM, 1969)

Random Sets in Subrecursive Hierarchies. - Robert A. Di Paola (J. ACM, 1969)

The Relational Data File and the Decision Problem for Classes of Proper Formulas. - Robert A. Di Paola (SIGIR, 1971)

The Solvability of the Decision Problem for Classes of Proper Formulas and Related Results. - Robert A. Di Paola (J. ACM, 1973)

A Theorem on Shortening the Length of Proof in Formal Systems of Arithmetic. - Robert A. Di Paola (J. Symb. Log., 1975)

The operator gap theorem in α-recursion theory. - Robert A. Di Paola (Arch. Math. Log., 1978)

A Lift of a Theorem of Friedberg: A Banach-Mazur Functional that Coincides with No alpha-Recursive Functional on the Class of alpha-Recursive Functions. - Robert A. Di Paola (J. Symb. Log., 1981)

Dominical Categories: Recursion Theory without Elements. - Robert A. Di Paola; Alex Heller (J. Symb. Log., 1987)

Some Properties of the Syntactic p-Recursion Categories Generated by Consistent, Recursively Enumerable Extensions of Peano Arithmetic. - Robert A. Di Paola; Franco Montagna (J. Symb. Log., 1991)