@Article{ 
  BucCit18,
  author = { Bucur, Dorin and Cito, Simone },
  title = { Geometric control of the  Robin Laplacian eigenvalues: the case of negative boundary parameter },
  journal = { Journal of Geometric Analysis },
  year = { 2019 },
  doi = { DOI 10.1007/s12220-019-00245-9 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/4062/ },
  note = { cvgmt preprint}
}