An application of tarskis principle to absolute Galois groups of function fields. - Lou van den Dries; Paulo Ribenboim (Ann. Pure Appl. Log., 1987)

Ultrametric Spaces and Logic Programming. - Sibylla Priess-Crampe; Paulo Ribenboim (J. Log. Program., 2000)

Explicit Solutions of Certain Systems of Pell Equations. - Paulo Ribenboim (Integers, 2012)