1. Cambridge Tracts in Mathematics;E.B. Davies,1989
2. Fabes, E.B., Gutiérrez, C.E., and Scotto, R. (1994). Weak-type estimates for the Riesz transforms associated with the Gaussian measure.Revista Matemática Iberoamericana,10.
3. Forzani, L. and Scotto, R. The higher order Riesz transform for Gaussian measure need not be weak type (1, 1), to appear.
4. García-Cuerva, J., Mauceri, G., Sjögren P., and Torrea, J.L. Higher-order Riesz operators for the Ornstein-Uhlenbeck semigroup, Preprint 1996–34, Department of Mathematics. Chalmers University of Technology and University of Göteborg.
5. Gundy, R.F. (1986). Sur les transformations de Riesz pour le semigroupe d’Ornstein-Uhlenbeck.C. R. Acad. Sci. 303, 967–970.