@Article{ MetPalPri2, author = { Metafune, Giorgio and Pallara, Diego and Priola, Enrico }, title = { Spectrum of Ornstein-Uhlenbeck operators in $L^p$ spaces with respect to invariant measures }, journal = { J. Funct. Anal. }, year = { 2002 }, volume = { 196 }, pages = { 40-60 }, URL = { http://cvgmt.sns.it/paper/2487/ }, note = { cvgmt preprint} }