@Misc{ 
  dra06a,
  author = { Dragoni, Federica },
  title = { Carnot-Carathéodory metrics and viscosity solutions },
  journal = {  },
  year = { 2006 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/527/ },
  note = { cvgmt preprint}
}