@Misc{ 
  amb05,
  author = { Ambrosio, Luigi },
  title = { Transport equation and Cauchy problem for non-smooth vector fields  },
  journal = {  },
  year = { 2005 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/1149/ },
  note = { cvgmt preprint}
}