@Misc{ BraSan16a, author = { Brasco, Lorenzo and Santambrogio, Filippo }, title = { A sharp estimate à la Calderón-Zygmund for the $p-$Laplacian }, journal = { Commun. Contemp. Math. }, year = { 2017 }, doi = { 10.1142/S0219199717500304 }, pages = { 22 pages }, URL = { http://cvgmt.sns.it/paper/3121/ }, note = { cvgmt preprint} }