@Article{ 
  foc,
  author = { Focardi, Matteo },
  title = { Homogenization of fractional obstacle problems via $\Gamma$-convergence },
  journal = { Comm. Partial Differential Equations },
  year = { 2009 },
  volume = { 34 },
  pages = { 1607-1631 },
  URL = { http://cvgmt.sns.it/paper/1113/ },
  note = { cvgmt preprint}
}