@Misc{ 
  bergaz05,
  author = { Berchio, Elvise and Gazzola, Filippo },
  title = { Best constants and minimizers for embeddings of second order Sobolev spaces },
  journal = {  },
  year = { 2005 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/663/ },
  note = { cvgmt preprint}
}