@article{JEMS_2008_10_2_a6,
     author = {Jean Van Schaftingen and Michel Willem},
     title = {Symmetry of solutions of semilinear elliptic problems},
     journal = {Journal of the European Mathematical Society},
     pages = {439--456},
     publisher = {mathdoc},
     volume = {10},
     number = {2},
     year = {2008},
     doi = {10.4171/jems/117},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/jems/117/}
}