@Article{ MetPalWac2, author = { Metafune, Giorgio and Pallara, Diego and Wacker, Marcus }, title = { Feller semigroups on ${\bf R}^N$ }, journal = { Semigroup Forum }, year = { 2002 }, volume = { 65 }, pages = { 159-205 }, URL = { http://cvgmt.sns.it/paper/2549/ }, note = { cvgmt preprint} }