@article{10_1017_fms_2014_24,
     author = {DAVID DE LAAT and FERNANDO M\'ARIO DE OLIVEIRA FILHO and FRANK VALLENTIN},
     title = {Upper bounds for packings of spheres of several radii},
     journal = {Forum of Mathematics, Sigma},
     publisher = {mathdoc},
     volume = {2},
     year = {2014},
     doi = {10.1017/fms.2014.24},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/fms.2014.24/}
}