@Misc{ 
  BarFigRos17a,
  author = { Barrios, Begoña and Figalli, Alessio and Ros-Oton, Xavier },
  title = { Free boundary regularity in the parabolic fractional obstacle problem },
  journal = { Comm. Pure Appl. Math. },
  year = { 2017 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/3504/ },
  note = { cvgmt preprint}
}