@article{MZM_1989_45_3_a12,
     author = {I. R. Shafarevich},
     title = {Factors of a descending central series},
     journal = {Matemati\v{c}eskie zametki},
     pages = {114--117},
     publisher = {mathdoc},
     volume = {45},
     number = {3},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1989_45_3_a12/}
}