@Article{ 
  ambsan05,
  author = { Ambrosio, Luigi and Santambrogio, Filippo },
  title = { Necessary optimality conditions for geodesics in weighted Wasserstein spaces },
  journal = { Rend. Lincei - Mat. e Appl. },
  year = { 2007 },
  volume = { 18 },
  number = { 1 },
  pages = { 23 - 37 },
  URL = { http://cvgmt.sns.it/paper/146/ },
  note = { cvgmt preprint}
}