@article{DAN_1972_204_1_a1,
     author = {Yu. M. Gorchakov and G. P. Egorychev},
     title = {Ranks of factors of the lower central series of a free polynilpotent group},
     journal = {Doklady Akademii Nauk},
     pages = {12--14},
     publisher = {mathdoc},
     volume = {204},
     number = {1},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1972_204_1_a1/}
}