@article{MZM_2018_103_5_a4,
     author = {A. V. Zhuchok},
     title = {Free $n${-Tuple} {Semigroups}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {693--701},
     publisher = {mathdoc},
     volume = {103},
     number = {5},
     year = {2018},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2018_103_5_a4/}
}