@article{UZKU_2020_162_3_a2,
     author = {T. V. Andreeva and Yu. S. Semenov},
     title = {On the cardinality of layers in some partially ordered sets},
     journal = {U\v{c}\"enye zapiski Kazanskogo universiteta. Seri\^a Fiziko-matemati\v{c}eskie nauki},
     pages = {269--284},
     publisher = {mathdoc},
     volume = {162},
     number = {3},
     year = {2020},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/UZKU_2020_162_3_a2/}
}