@Misc{ 
  crufio,
  author = { Cruz-Uribe, David and Fiorenza, Alberto },
  title = { Endpoint estimates and weighted norm inequalities for commutators of fractional integrals },
  journal = { Publicacions Matematiques },
  year = { 2002 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/1130/ },
  note = { cvgmt preprint}
}