@article{CMH_1984__59_139979,
     author = {Micheal Dyer},
     title = {Subgroups with projective abelianization and trivial multiplicator.},
     journal = {Commentarii mathematici Helvetici},
     pages = {333--340},
     publisher = {mathdoc},
     volume = {59},
     year = {1984},
     zbl = {0545.20025},
     url = {http://geodesic.mathdoc.fr/item/CMH_1984__59_139979/}
}