@article{IM2_2016_80_3_a8,
     author = {E. I. Timoshenko},
     title = {Universal theory of a~free polynilpotent group},
     journal = {Izvestiya. Mathematics },
     pages = {623--632},
     publisher = {mathdoc},
     volume = {80},
     number = {3},
     year = {2016},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_2016_80_3_a8/}
}