@article{MAN_1983__264_163785,
     author = {J\"urgen Ritter and Sudarshan K. Sehgal},
     title = {On a {Conjecture} of {Zassenhaus} on {Torsion} {Units} in {Integral} {Group} {Rings.}},
     journal = {Mathematische Annalen},
     pages = {257--270},
     publisher = {mathdoc},
     volume = {264},
     year = {1983},
     zbl = {0521.16006},
     url = {http://geodesic.mathdoc.fr/item/MAN_1983__264_163785/}
}