@article{GDZPPN002239108,
title = {Finitely Generated pro-2 Groups with a free subgroup of Index 2.},
journal = {Manuscripta mathematica},
volume = {94},
year = {1997},
pages = {457-464},
zbl = {0951.20018},
url = {http://dml.mathdoc.fr/item/GDZPPN002239108}
}
Herfort, W.; Zalesskii, P. Finitely Generated pro-2 Groups with a free subgroup of Index 2.. Manuscripta mathematica, Tome 94 (1997) pp. 457-464. http://gdmltest.u-ga.fr/item/GDZPPN002239108/