@Misc{ 
  valvas03,
  author = { Chiadò Piat, Valeria and Zhikov, Vasily Vasilievich },
  title = { Relaxation problems in Sobolev spaces with respect to a measure },
  journal = {  },
  year = { 2003 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/98/ },
  note = { cvgmt preprint}
}