@Article{ 
  san09,
  author = { Santambrogio, Filippo },
  title = { A Modica-Mortola approximation for branched transport },
  journal = { Comptes Rendus Acad. Sci. },
  year = { 2010 },
  volume = { 348 },
  pages = { 941-945 },
  URL = { http://cvgmt.sns.it/paper/230/ },
  note = { cvgmt preprint}
}