@article{GDZPPN002061481,
title = {Amalgamated Free Products of Groups and Homological Duality},
journal = {Commentarii mathematici Helvetici},
volume = {49},
year = {1974},
pages = {460-478},
zbl = {0304.20034},
url = {http://dml.mathdoc.fr/item/GDZPPN002061481}
}
Bieri, Robert; Eckmann, Benno. Amalgamated Free Products of Groups and Homological Duality. Commentarii mathematici Helvetici, Tome 49 (1974) pp. 460-478. http://gdmltest.u-ga.fr/item/GDZPPN002061481/