@Article{ 
  Tor21,
  author = { Tortone, Giorgio },
  title = { Regularity of shape optimizers for some spectral fractional problems },
  journal = { Journal of Functional Analysis },
  year = { 2021 },
  doi = { 10.1016/j.jfa.2021.109271 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/6272/ },
  note = { cvgmt preprint}
}