@Misc{ 
  BraBut14,
  author = { Brasco, Lorenzo and Buttazzo, Giuseppe },
  title = { Improved energy bounds for Schrödinger operators },
  journal = { Calc. Var. Partial Differential Equations },
  year = { 2014 },
  pages = { 31 },
  URL = { http://cvgmt.sns.it/paper/2373/ },
  note = { cvgmt preprint}
}