@article{JRAM_1967__227_150808,
     author = {N. Nobusawa},
     title = {On class numbers of lattices in isotropic spaces.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {209--211},
     publisher = {mathdoc},
     volume = {227},
     year = {1967},
     zbl = {0204.07404},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1967__227_150808/}
}