@article{DM_2021_33_3_a1,
     author = {C. I. Groshev},
     title = {On a class of irregular languages},
     journal = {Diskretnaya Matematika},
     pages = {41--45},
     publisher = {mathdoc},
     volume = {33},
     number = {3},
     year = {2021},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DM_2021_33_3_a1/}
}