@article{SM_1972_18_1_a5,
     author = {N. S. Romanovskii},
     title = {A~freedom theorem for groups with one defining relation in the varieties of solvable and nilpotent groups of given lengths},
     journal = {Sbornik. Mathematics},
     pages = {93--99},
     publisher = {mathdoc},
     volume = {18},
     number = {1},
     year = {1972},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1972_18_1_a5/}
}