@article{1255630890, author = {Gruenberg, K. W.}, title = {The upper central series in soluble groups}, journal = {Illinois J. Math.}, volume = {5}, number = {1}, year = {1961}, pages = { 436-466}, language = {en}, url = {http://dml.mathdoc.fr/item/1255630890} }
Gruenberg, K. W. The upper central series in soluble groups. Illinois J. Math., Tome 5 (1961) no. 1, pp. 436-466. http://gdmltest.u-ga.fr/item/1255630890/