@article{AIHPC_2001__18_2_135_0,
     author = {Sirakov, Boyan},
     title = {Symmetry for exterior elliptic problems and two conjectures in potential theory},
     journal = {Annales de l'I.H.P. Analyse non lin\'eaire},
     pages = {135--156},
     publisher = {Elsevier},
     volume = {18},
     number = {2},
     year = {2001},
     mrnumber = {1808026},
     zbl = {0997.35014},
     language = {en},
     url = {http://www.numdam.org/item/AIHPC_2001__18_2_135_0/}
}