@article{IM_1993__114_1_144156,
     author = {Alejandro Adem},
     title = {Characters and {K-theory} of discrete groups.},
     journal = {Inventiones mathematicae},
     pages = {489--514},
     year = {1993},
     volume = {114},
     number = {1},
     zbl = {0804.55002},
     url = {http://geodesic.mathdoc.fr/item/IM_1993__114_1_144156/}
}