@article{CMUC_1980__21_2_a17,
     author = {Jackett, David R.},
     title = {The nil-degree of a torsion-free {Abelian} group},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {393--406},
     publisher = {mathdoc},
     volume = {21},
     number = {2},
     year = {1980},
     mrnumber = {580694},
     zbl = {0436.20034},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1980__21_2_a17/}
}