@Article{ 
  BarBesLer18,
  author = { Barilari, Davide and Beschastnyi, Ivan and Lerario, Antonio },
  title = { Volume of small balls and sub-Riemannian curvature in 3D contact manifolds },
  journal = { Journal of Symplectic Geometry },
  year = { 2020 },
  doi = { https://dx.doi.org/10.4310/JSG.2020.v18.n2.a1 },
  volume = { 18 },
  number = { 2 },
  pages = { 355-384 },
  URL = { http://cvgmt.sns.it/paper/3785/ },
  note = { cvgmt preprint}
}