@Misc{ 
  BalCitCup16,
  author = { Baldi, Annalisa and Citti, Giovanna and Cupini, Giovanni },
  title = { Schauder estimates at the boundary for sub-laplacians in Carnot groups },
  journal = { Calc. Var. Partial Differential Equations },
  year = { 2019 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/3197/ },
  note = { cvgmt preprint}
}