@Article{ 
  BruColDeL20,
  author = { Bruè, Elia and Colombo, Maria and De Lellis, Camillo },
  title = { Positive solutions of transport equations and classical nonuniqueness of characteristic curves },
  journal = { Arch. Rat. Mech. Anal. },
  year = { 2020 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/4610/ },
  note = { cvgmt preprint}
}