@Article{ 
  ComSte22,
  author = { Comi, Giovanni Eugenio and Stefani, Giorgio },
  title = { Failure of the local chain rule for the fractional variation },
  journal = { Port. Math. },
  year = { 2023 },
  doi = { 10.4171/PM/2096 },
  volume = { 80 },
  number = { 1-2 },
  pages = { 1-25 },
  URL = { http://cvgmt.sns.it/paper/5562/ },
  note = { cvgmt preprint}
}