@article{SM_1969_8_1_a1,
     author = {N. R. Brumberg},
     title = {On~the commutator subgroup of two varieties of groups},
     journal = {Sbornik. Mathematics},
     pages = {33--51},
     publisher = {mathdoc},
     volume = {8},
     number = {1},
     year = {1969},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1969_8_1_a1/}
}