@article{DM_2018_30_3_a3,
     author = {I. E. Ivanov},
     title = {Periodic properties of pushdown automata},
     journal = {Diskretnaya Matematika},
     pages = {40--47},
     publisher = {mathdoc},
     volume = {30},
     number = {3},
     year = {2018},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DM_2018_30_3_a3/}
}