@Misc{ 
  CarSpi15,
  author = { Caravenna, Laura and Spinolo, Laura Valentina },
  title = { Schaeffer's regularity theorem for scalar conservation laws does not extend to systems },
  journal = {  },
  year = { 2015 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/2684/ },
  note = { cvgmt preprint}
}