@Misc{ 
  Bra13,
  author = { Brasco, Lorenzo },
  title = { On torsional rigidity and principal frequencies: an invitation to the Kohler-Jobin rearrangement technique },
  journal = { ESAIM: COCV },
  year = { 2013 },
  pages = { 27 },
  URL = { http://cvgmt.sns.it/paper/2083/ },
  note = { cvgmt preprint}
}