@article{CMH_1970__45_139439,
     author = {Urs Stammbach},
     title = {Homological {Methods} in {Group} {Varieties.}},
     journal = {Commentarii mathematici Helvetici},
     pages = {287--298},
     publisher = {mathdoc},
     volume = {45},
     year = {1970},
     zbl = {0195.03703},
     url = {http://geodesic.mathdoc.fr/item/CMH_1970__45_139439/}
}