@Misc{ 
  magvil06,
  author = { Maggi, Francesco and Villani, Cédric },
  title = { Balls have the worst best Sobolev inequalities. Part II: Variants and extensions },
  journal = { Calc. Var. Partial Differential Equations },
  year = { 2007 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/222/ },
  note = { cvgmt preprint}
}