@article{GDZPPN002060574,
title = {On the Homology Theory of Central Group Extensions: I - The Commutator Map and Stem Extensions},
journal = {Commentarii mathematici Helvetici},
volume = {47},
year = {1972},
pages = {102-122},
zbl = {0236.20038},
url = {http://dml.mathdoc.fr/item/GDZPPN002060574}
}
Eckmann, Beno; Stammbach, Urs; Hilton, Peter J. On the Homology Theory of Central Group Extensions: I - The Commutator Map and Stem Extensions. Commentarii mathematici Helvetici, Tome 47 (1972) pp. 102-122. http://gdmltest.u-ga.fr/item/GDZPPN002060574/