@article{PFMT_2017_4_a12,
     author = {A. A. Pypka},
     title = {On the numerical characteristics of the factors of the central series and their relationships in some algebraic structures},
     journal = {Problemy fiziki, matematiki i tehniki},
     pages = {71--75},
     publisher = {mathdoc},
     number = {4},
     year = {2017},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/PFMT_2017_4_a12/}
}