@Article{ 
  Cat14,
  author = { Catino, Giovanni },
  title = { Some rigidity results on critical metrics for quadratic functionals },
  journal = { Calc. Var. Partial Differential Equations },
  year = { 2015 },
  volume = { 54 },
  number = { 3 },
  pages = { 2921-2937 },
  URL = { http://cvgmt.sns.it/paper/2402/ },
  note = { cvgmt preprint}
}