@Article{ 
  fer06a,
  author = { Ferriero, Alessandro },
  title = { The weak repulsion property },
  journal = { J. Math. Pures Appl. },
  year = { 2007 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/999/ },
  note = { cvgmt preprint}
}