@Misc{ 
  biacar09,
  author = { Bianchini, Stefano and Caravenna, Laura },
  title = { On the extremality, uniqueness and optimality of transference plans },
  journal = {  },
  year = { 2009 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/1143/ },
  note = { cvgmt preprint}
}