@Misc{ 
  Cat12,
  author = { Catino, Giovanni },
  title = { Critical metrics of the $L^2$-norm of the scalar curvature },
  journal = {  },
  year = { 2012 },
  pages = {  },
  URL = { https://gecogedi.dimai.unifi.it/paper/536/ },
  note = { cvgmt preprint}
}