@Article{ 
  mag09a,
  author = { Magnani, Valentino },
  title = { Area implies coarea },
  journal = {  Indiana Univ. Math. J. },
  year = { 2011 },
  volume = { 60 },
  pages = { 77-100 },
  URL = { http://cvgmt.sns.it/paper/234/ },
  note = { cvgmt preprint}
}