@Misc{ 
  FocGerSpa16,
  author = { Focardi, Matteo and Geraci, Francesco and Spadaro, Emanuele },
  title = { The classical obstacle problem for nonlinear variational energies },
  journal = {  },
  year = { 2016 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/3225/ },
  note = { cvgmt preprint}
}