@Article{ 
  DeRTio19a,
  author = { De Rosa , Luigi and Tione, Riccardo },
  title = { On a question of D. Serre },
  journal = { ESAIM: COCV },
  year = { 2020 },
  doi = { https://doi.org/10.1051/cocv/2020021 },
  volume = { 26 },
  number = { 97 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/4915/ },
  note = { cvgmt preprint}
}