@article{DAN_1978_242_3_a7,
     author = {G. A. Margulis},
     title = {Factor groups of discrete subgroups},
     journal = {Doklady Akademii Nauk},
     pages = {533--536},
     publisher = {mathdoc},
     volume = {242},
     number = {3},
     year = {1978},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1978_242_3_a7/}
}