@Misc{ 
  dangarnhi02,
  author = { Danielli, Donatella and Garofalo, Nicola and Nhieu, Duy-Minh },
  title = { Non-doubling Ahlfors measures, Perimeter measures, and the characterization of the trace spaces of Sobolev functions in Carnot-Carathéodory spaces },
  journal = { Memoirs Amer. Math. Soc. },
  year = { 2003 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/280/ },
  note = { cvgmt preprint}
}