@article{GDZPPN002356570, title = {Nielsen methods in groups with a length function.}, journal = {Mathematica Scandinavica}, volume = {48}, year = {1981}, pages = {153-164}, zbl = {0463.20023}, url = {http://dml.mathdoc.fr/item/GDZPPN002356570} }
Hoare, A.H.M. Nielsen methods in groups with a length function.. Mathematica Scandinavica, Tome 48 (1981) pp. 153-164. http://gdmltest.u-ga.fr/item/GDZPPN002356570/