@Misc{ 
  PaoPisSan20,
  author = { Paoli, Gloria and Piscitelli, Gianpaolo and Sannipoli, Rossano },
  title = { A stability result for the Steklov Laplacian Eigenvalue Problem with a
  spherical obstacle },
  journal = {  },
  year = { 2020 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/5701/ },
  note = { cvgmt preprint}
}