@Misc{ 
  fraserser01a,
  author = { Franchi, Bruno and Serapioni, Raul and Serra Cassano, Francesco },
  title = { Regular hypersurfaces, Intrinsic perimeter and implicit function theorem in Carnot groups },
  journal = { Comm. Analysis and Geometry },
  year = { 2002 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/1346/ },
  note = { cvgmt preprint}
}