@article{GDZPPN00206541X,
title = {Subgroups with projective abelianization and trivial multiplicator.},
journal = {Commentarii mathematici Helvetici},
volume = {59},
year = {1984},
pages = {333-340},
zbl = {0545.20025},
url = {http://dml.mathdoc.fr/item/GDZPPN00206541X}
}
Dyer, Micheal. Subgroups with projective abelianization and trivial multiplicator.. Commentarii mathematici Helvetici, Tome 59 (1984) pp. 333-340. http://gdmltest.u-ga.fr/item/GDZPPN00206541X/