%0 Journal Article %A Hamel, François %A Nadirashvili, Nikolai %A Russ, Emmanuel %T Some isoperimetric problems for the principal eigenvalues of second-order elliptic operators in divergence form %J Comptes Rendus. Mathématique %D 2007 %P 169-174 %V 344 %N 3 %I Elsevier %U http://www.numdam.org/articles/10.1016/j.crma.2006.11.025/ %R 10.1016/j.crma.2006.11.025 %G en %F CRMATH_2007__344_3_169_0