@Article{ 
  BraFra12,
  author = { Brasco, Lorenzo and Franzina, Giovanni },
  title = { A note on positive eigenfunctions and hidden convexity },
  journal = { Arch. Math. },
  year = { 2012 },
  pages = { 7 },
  URL = { http://cvgmt.sns.it/paper/1852/ },
  note = { cvgmt preprint}
}