A Note on a Unifying Proof of the Undecidability of Several Diagrammatic Properties of Term Rewriting Systems. - António Malheiro; Paulo Guilherme Santos (CoRR, 2019)

Variants of Kreisel's Conjecture on a New Notion of Provability. - Paulo Guilherme Santos; Reinhard Kahle (Bull. Symb. Log., 2021)

k-Provability in $ hbox {PA}$. - Paulo Guilherme Santos; Reinhard Kahle (Logica Universalis, 2021)

A new perspective on completeness and finitist consistency. - Paulo Guilherme Santos; Wilfried Sieg; Reinhard Kahle (J. Log. Comput., 2024)

Numeral completeness of weak theories of arithmetic. - Reinhard Kahle; Isabel Oitavem; Paulo Guilherme Santos (J. Log. Comput., 2025)