@article{GDZPPN002084643,
title = {Canonical bases for normal subgroups of finitely generated free groups with finite abelian factor groups.},
journal = {Forum mathematicum},
volume = {5},
year = {1993},
pages = {23-32},
zbl = {0799.20026},
url = {http://dml.mathdoc.fr/item/GDZPPN002084643}
}
Baumann, Bernd; C.M., Scoppola. Canonical bases for normal subgroups of finitely generated free groups with finite abelian factor groups.. Forum mathematicum, Tome 5 (1993) pp. 23-32. http://gdmltest.u-ga.fr/item/GDZPPN002084643/