@article{MZ_1991__206_1_174207,
     author = {R. Bieri and J.A. Hillmann},
     title = {Subnormal subgroups of 3-dimensional {Poincar\'e} duality groups.},
     journal = {Mathematische Zeitschrift},
     pages = {67--70},
     publisher = {mathdoc},
     volume = {206},
     number = {1},
     year = {1991},
     zbl = {0695.57001},
     url = {http://geodesic.mathdoc.fr/item/MZ_1991__206_1_174207/}
}