@article{SM_2016_207_12_a2,
     author = {A. V. Grishin and S. V. Pchelintsev},
     title = {Proper central and core polynomials of relatively free associative algebras with identity of {Lie} nilpotency of degrees 5 and~6},
     journal = {Sbornik. Mathematics},
     pages = {1674--1692},
     publisher = {mathdoc},
     volume = {207},
     number = {12},
     year = {2016},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2016_207_12_a2/}
}