@Misc{ 
  gigc,
  author = { Gigli, Nicola },
  title = { On the inverse implication of Brenier-McCann theorems and the structure of $(P_2(M),W_2)$ },
  journal = { Meth. Appl. of Anal. },
  year = { 2009 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/983/ },
  note = { cvgmt preprint}
}