@Article{ 
  AnGoMiPi17,
  author = { Antonucci, Clara and Gobbino, Massimo and Migliorini, Matteo and Picenni, Nicola },
  title = { Optimal constants for a non-local approximation of Sobolev norms and  total variation },
  journal = { Anal. PDE },
  year = { 2020 },
  doi = { https://doi.org/10.2140/apde.2020.13.595 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/3539/ },
  note = { cvgmt preprint}
}