@Misc{ 
  CupLan19,
  author = { Cupini, Giovanni and Lanconelli, Ermanno },
  title = { On Mean Value formulas for solutions to linear second order PDEs },
  journal = {  },
  year = { 2019 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/4323/ },
  note = { cvgmt preprint}
}