@article{JRAM_1982__334_152448,
     author = {Wilhelm Plesken},
     title = {Counting with groups and rings.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {40--68},
     year = {1982},
     volume = {334},
     zbl = {0476.20041},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1982__334_152448/}
}