@Misc{ 
  Mon18,
  author = { Monti, Roberto },
  title = { The regularity problem for geodesics of the control distance },
  journal = { Bruno Pini Mathematical Analysis Seminar, 2018, 9,  137--146 },
  year = { 2018 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/4467/ },
  note = { cvgmt preprint}
}