@Article{ 
  crafragaz03,
  author = { Crasta, Graziano and Fragalà, Ilaria and Gazzola, Filippo },
  title = { On a long-standing conjecture by Pólya-Szegö and related topics },
  journal = { Zeit. Angew. Math. Phys. },
  year = { 2005 },
  volume = { 56 },
  number = { 5 },
  pages = { 763-782 },
  URL = { http://cvgmt.sns.it/paper/246/ },
  note = { cvgmt preprint}
}