@article{MZ_1979__167_172846,
     author = {Jasbir Singh Chahal},
     title = {A {Note} on the {Discontinuous} {Subgroups} of the {Orthogonal} {Group.}},
     journal = {Mathematische Zeitschrift},
     pages = {181--186},
     publisher = {mathdoc},
     volume = {167},
     year = {1979},
     zbl = {0496.10011},
     url = {http://geodesic.mathdoc.fr/item/MZ_1979__167_172846/}
}