@article{10_4153_CMB_1998_063_4,
     author = {Parmenter, M. M. and Spiegel, E. and Stewart, P. N.},
     title = {The {Periodic} {Radical} of {Group} {Rings} and {Incidence} {Algebras}},
     journal = {Canadian mathematical bulletin},
     pages = {481--487},
     year = {1998},
     volume = {41},
     number = {4},
     doi = {10.4153/CMB-1998-063-4},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1998-063-4/}
}