@article{SM_1972_16_1_a1,
     author = {\`E. B. Vinberg},
     title = {On groups of unit elements of certain quadratic forms},
     journal = {Sbornik. Mathematics},
     pages = {17--35},
     year = {1972},
     volume = {16},
     number = {1},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1972_16_1_a1/}
}