@Article{ albboudal01, author = { Alberti, Giovanni and Bouchitté, Guy and Dal Maso, Gianni }, title = { The calibration method for the Mumford-Shah functional and free-discontinuity problems }, journal = { Calc. Var. Partial Differential Equations }, year = { 2003 }, volume = { 16 }, number = { 3 }, pages = { 299-333 }, URL = { http://cvgmt.sns.it/paper/1428/ }, note = { cvgmt preprint} }