@Article{ BriLam9b, author = { Briançon, Tanguy and Lamboley, Jimmy }, title = { Regularity of the optimal shapes for the first eigenvalue with volume and inclusion constraints }, journal = { Annales de l'IHP, Analyse non linéaire }, year = { 2009 }, volume = { 26 }, number = { 4 }, pages = { 1149-1163 }, URL = { http://cvgmt.sns.it/paper/3052/ }, note = { cvgmt preprint} }