@article{MAN_1976__224_162896,
     author = {Volker Flory},
     title = {Estimating {Norms} in {C*-Algebras} of {Discrete} {Groups.}},
     journal = {Mathematische Annalen},
     pages = {41--52},
     publisher = {mathdoc},
     volume = {224},
     year = {1976},
     zbl = {0337.22008},
     url = {http://geodesic.mathdoc.fr/item/MAN_1976__224_162896/}
}