@Misc{ 
  DePPalRin18,
  author = { De Philippis, Guido and Palmieri, Luca and Rindler, Filip },
  title = { On the two-state problem for general differential operators },
  journal = { Nonlinear Anal. },
  year = { 2018 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/3806/ },
  note = { cvgmt preprint}
}