@Article{ 
  Ros20,
  author = { Rossi, Tommaso },
  title = { Integrability of the sub-Riemannian mean curvature at degenerate  characteristic points in the Heisenberg group },
  journal = { Advances in Calculus of Variations },
  year = { 2021 },
  doi = { https://doi.org/10.1515/acv-2020-0098 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/4844/ },
  note = { cvgmt preprint}
}