@Misc{ 
  Nen16,
  author = { Nenna, Luca },
  title = { Numerical Methods for Multi-Marginal Optimal Transportation },
  journal = {  },
  year = { 2016 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/3272/ },
  note = { cvgmt preprint}
}