@Misc{ 
  AmbGigSav11b,
  author = { Ambrosio, Luigi and Gigli, Nicola and Savaré, Giuseppe },
  title = { Density of Lipschitz functions and equivalence of weak gradients in metric measure spaces },
  journal = {  },
  year = { 2011 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/1688/ },
  note = { cvgmt preprint}
}