@Article{ 
  BoaVit19,
  author = { Boarotto, Francesco and Vittone, Davide },
  title = { A dynamical approach to the Sard problem in Carnot groups },
  journal = { J. Differential Equations },
  year = { 2020 },
  doi = { http://dx.doi.org/10.1016/j.jde.2020.03.050 },
  volume = { 269 },
  pages = { 4998–5033 },
  URL = { http://cvgmt.sns.it/paper/4443/ },
  note = { cvgmt preprint}
}