@Article{ CafFig11, author = { Caffarelli, Luis and Figalli, Alessio }, title = { Regularity of solutions to the parabolic fractional obstacle problem }, journal = { J. Reine Angew. Math. }, year = { 2011 }, pages = { }, URL = { http://cvgmt.sns.it/paper/1672/ }, note = { cvgmt preprint} }