@Misc{ 
  delf,
  author = { Delladio, Silvano },
  title = { The set of regular values (in the sense of Clarke) of a Lipschitz map. A sufficient condition for the rectifiability of class $C^2$. },
  journal = {  },
  year = { 2007 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/156/ },
  note = { cvgmt preprint}
}