@Misc{ 
  boufra05,
  author = { Bouchitté, Guy and Fragalà, Ilaria },
  title = { Optimality conditions for mass design problems and applications to thin plates },
  journal = { Arch. Rat. Mech. Anal. },
  year = { 2006 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/11/ },
  note = { cvgmt preprint}
}