@article{EJDE_2006__2006__a151,
     author = {Didenko,  Andriy and Emamizadeh,  Behrouz},
     title = {A characterization of balls using the domain derivative},
     journal = {Electronic journal of differential equations},
     year = {2006},
     volume = {2006},
     zbl = {1128.35311},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2006__2006__a151/}
}