@article{VTPMK_2020_4_a0,
     author = {S. M. Dudakov},
     title = {On definability of one-symbol languages in the monoid of finite languages with concatenation},
     journal = {Vestnik Tverskogo gosudarstvennogo universiteta. Seri\^a Prikladna\^a matematika},
     pages = {5--13},
     publisher = {mathdoc},
     number = {4},
     year = {2020},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VTPMK_2020_4_a0/}
}