@Misc{ SpoVel17, author = { Spolaor, Luca and Velichkov, Bozhidar }, title = { An epiperimetric inequality for the regularity of some free boundary problems: the $2$-dimensional case }, journal = { Comm. Pure Appl. Math. }, year = { 2017 }, pages = { 32 }, URL = { http://cvgmt.sns.it/paper/3334/ }, note = { cvgmt preprint} }