@Misc{ 
  CitGia23,
  author = { Cito, Simone and Giacomini, Alessandro },
  title = { Minimization of the $k$-th eigenvalue of the Robin-Laplacian with perimeter constraint },
  journal = {  },
  year = { 2023 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/6342/ },
  note = { cvgmt preprint}
}