@Article{ 
  BarGof20,
  author = { Bardi, Martino and Goffi, Alessandro },
  title = { Liouville results for fully nonlinear equations modeled on Hörmander vector fields: I. The Heisenberg group },
  journal = { Mathematische Annalen },
  year = { 2022 },
  doi = { 10.1007/s00208-020-02118-x },
  volume = { 383 },
  pages = { 171-201 },
  URL = { http://cvgmt.sns.it/paper/4702/ },
  note = { cvgmt preprint}
}