@Misc{ 
  AcaAmaCri23,
  author = { Acampora, Paolo and Amato, Vincenzo and Cristoforoni, Emanuele },
  title = { Estimates on the Neumann and Steklov principal eigenvalues of collapsing
  domains },
  journal = {  },
  year = { 2023 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/6663/ },
  note = { cvgmt preprint}
}