@Article{ Pra15, author = { Pratelli, Aldo }, title = { A survey on the existence of isoperimetric sets in the space $\mathbb R^N$ with density }, journal = { Atti Accad. Naz. Lincei Rend. Lincei Mat. Appl. }, year = { 2015 }, pages = { }, URL = { http://cvgmt.sns.it/paper/2625/ }, note = { cvgmt preprint} }