@Misc{ 
  DiDFäsOrp19,
  author = { Di Donato, Daniela and Fässler, Katrin and Orponen, Tuomas },
  title = { Metric rectifiability of $\mathbb{H}$-regular surfaces with Hölder
  continuous horizontal normal },
  journal = {  },
  year = { 2019 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/4716/ },
  note = { cvgmt preprint}
}