@article{JRAM_1987__381_152979,
     author = {J\"urgen Ritter and Sudarshan K. Sehgal},
     title = {Certain normal subgroups of units in group rings.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {214--220},
     publisher = {mathdoc},
     volume = {381},
     year = {1987},
     zbl = {0618.16006},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1987__381_152979/}
}