@article{MAN_1976__224_162910,
     author = {Marie-France Vign\'eras},
     title = {Invariants num\'eriques des groupes de {Hilbert.}},
     journal = {Mathematische Annalen},
     pages = {189--216},
     publisher = {mathdoc},
     volume = {224},
     year = {1976},
     zbl = {0325.12004},
     url = {http://geodesic.mathdoc.fr/item/MAN_1976__224_162910/}
}