Fractional integration and fractional differentiation for Jacobi expansions. Balderrama, Cristina; Urbina, Wilfredo — 2007 Divulgaciones Matemáticas
On singular integrals with respect to the gaussian measure Wilfredo Urbina — 1990 Annali della Scuola Normale Superiore di Pisa - Classe di Scienze
Non tangential convergence for the Ornstein-Uhlenbeck semigroup. Pineda, Ebner; Urbina R., Wilfredo — 2008 Divulgaciones Matemáticas
A simple proof of the L p continuity of the higher order Riesz transforms with respect to the gaussian measure γ d Liliana Forzani; Roberto Scotto; Wilfredo Urbina — 2001 Séminaire de probabilités de Strasbourg