@Misc{ 
  butgua97,
  author = { Buttazzo, Giuseppe and Guasoni, Paolo },
  title = { Shape Optimization Problems over Classes of Convex Domains },
  journal = { J. Convex Analysis },
  year = { 1997 },
  number = { 4-2 },
  pages = { 1-9 },
  URL = { http://cvgmt.sns.it/paper/1433/ },
  note = { cvgmt preprint}
}