@Misc{ 
  SpoTreVel18,
  author = { Spolaor, Luca and Trey, Baptiste and Velichkov, Bozhidar },
  title = { Free boundary regularity for a multiphase shape optimization problem },
  journal = { Communications in Partial Differential Equations },
  year = { 2018 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/4073/ },
  note = { cvgmt preprint}
}