@article{RMC_2009_2009_1_a20,
     author = {Kalis, Jan and  Milman, Mario},
     title = {Symmetrization and sharp {Sobolev} inequalities in metric spaces.},
     journal = {Revista matem\'atica complutense},
     publisher = {mathdoc},
     volume = {22},
     number = {2},
     year = {2009},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RMC_2009_2009_1_a20/}
}