@article {2003,
	title = {The calibration method for the Mumford-Shah functional and free-discontinuity problems},
	journal = {Calc. Var. Partial Differential Equations 16 (2003) 299-333},
	number = {SISSA;35/2001/M},
	year = {2003},
	publisher = {Springer},
	abstract = {We present a minimality criterion for the Mumford-Shah functional, and more generally for non convex variational integrals on SBV which couple a surface and a bulk term. This method provides short and easy proofs for several minimality results.},
	doi = {10.1007/s005260100152},
	url = {http://hdl.handle.net/1963/3051},
	author = {Giovanni Alberti and Guy Bouchitte and Gianni Dal Maso}
}
@article {1999,
	title = {The calibration method for the Mumford-Shah functional},
	journal = {C. R. Acad. Sci. Paris Ser. I Math. 329 (1999), no. 3, 249-254},
	number = {SISSA;21/99/M},
	year = {1999},
	publisher = {Elsevier},
	abstract = {In this Note we adapt the calibration method to functionals of Mumford-Shah type, and provide a criterion (Theorem 1) to verify that a given function is energy minimizing. Among other applications, we use this criterion to show that certain triple-junction configurations are minimizing (Example 3).},
	doi = {10.1016/S0764-4442(00)88602-4},
	url = {http://hdl.handle.net/1963/1235},
	author = {Giovanni Alberti and Guy Bouchitte and Gianni Dal Maso}
}
