@article{NUMA_1972__19_132162,
     author = {H. Zassenhaus and J. Neub\"user and H. Brown},
     title = {On {Integral} {Groups.} {I.} {The} {Reducible} {Case.}},
     journal = {Numerische Mathematik},
     pages = {386--399},
     publisher = {mathdoc},
     volume = {19},
     year = {1972},
     zbl = {0244.20056},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1972__19_132162/}
}