@Article{ 
  gra,
  author = { Granieri, Luca },
  title = { A distance representation of Kantorovich potentials },
  journal = { Applied Mathematics Letters },
  year = { 2009 },
  volume = { 22 },
  number = { 4 },
  pages = { 605-610 },
  URL = { http://cvgmt.sns.it/paper/910/ },
  note = { cvgmt preprint}
}