@Misc{ CagColDeP13, author = { Cagnetti, Filippo and Colombo, Maria and De Philippis, Guido and Maggi, Francesco }, title = { Rigidity of equality cases in Steiner's perimeter inequality }, journal = { Anal. PDE }, year = { 2013 }, pages = { }, URL = { http://cvgmt.sns.it/paper/2230/ }, note = { cvgmt preprint} }