@article{GDZPPN002438917, title = {Subgroup separability and 3-manifold groups.}, journal = {Mathematische Zeitschrift}, volume = {207}, year = {1991}, pages = {209-216}, zbl = {0711.57002}, url = {http://dml.mathdoc.fr/item/GDZPPN002438917} }
Long, D.D.; Niblo, G.A. Subgroup separability and 3-manifold groups.. Mathematische Zeitschrift, Tome 207 (1991) pp. 209-216. http://gdmltest.u-ga.fr/item/GDZPPN002438917/