@Misc{ 
  BiaBra23,
  author = { Bianchi, Francesca and Brasco, Lorenzo },
  title = { An optimal lower bound in fractional spectral geometry for planar sets with topological constraints },
  journal = { J. London Math. Soc. },
  year = { 2023 },
  pages = {  },
  URL = { http://cvgmt.sns.it/paper/5882/ },
  note = { cvgmt preprint}
}