%0 Journal Article %A Didenko, Andriy %A Emamizadeh, Behrouz %T A characterization of balls using the domain derivative %J Electronic Journal of Differential Equations %D 2006 %V 2006 %I mathdoc %U http://geodesic.mathdoc.fr/item/EJDE_2006__2006__a51/ %G en %F EJDE_2006__2006__a51