@Article{ 
  fonleopar,
  author = { Fonseca, Irene and Leoni, Giovanni and Paroni, Roberto },
  title = { On Hessian Matrices in the Space $BH$ },
  journal = { Commun. Contemp. Math. },
  year = { 2005 },
  volume = { 7 },
  number = { 4 },
  pages = {  401-420 },
  URL = { http://cvgmt.sns.it/paper/120/ },
  note = { cvgmt preprint}
}