@Article{ magvil, author = { Maggi, Francesco and Villani, Cédric }, title = { Balls Have the Worst Best Sobolev Inequalities }, journal = { J. Geom. Anal. }, year = { 2005 }, volume = { 15 }, number = { 1 }, pages = { 83-121 }, URL = { http://cvgmt.sns.it/paper/555/ }, note = { cvgmt preprint} }