@Article{ 
  albboudal99,
  author = { Alberti, Giovanni and Bouchitté, Guy and Dal Maso, Gianni },
  title = { The Calibration Method for the Mumford-Shah Functional },
  journal = { C. R. Acad. Sci. Paris Sér. I Math. },
  year = { 1999 },
  volume = { 329 (1999) },
  number = { 3 },
  pages = { 249-254 },
  URL = { http://cvgmt.sns.it/paper/506/ },
  note = { cvgmt preprint}
}