@Article{ 
  albbiacri11,
  author = { Alberti, Giovanni and Bianchini, Stefano and Crippa, Gianluca },
  title = { Structure of level sets and Sard-type properties of Lipschitz maps },
  journal = { Ann. Scuola Norm. Sup. Pisa Cl. Sci. (5) },
  year = { 2013 },
  doi = { 10.2422/2036-2145.201107_006 },
  volume = { 12 },
  number = { 4 },
  pages = { 863-902 },
  URL = { http://cvgmt.sns.it/paper/1475/ },
  note = { cvgmt preprint}
}