@article{DM_1989_1_3_a4,
     author = {A. V. Kostochka},
     title = {An upper bound on the capacity of the boundary of an antichain in an $n$-dimensional cube},
     journal = {Diskretnaya Matematika},
     pages = {53--61},
     year = {1989},
     volume = {1},
     number = {3},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DM_1989_1_3_a4/}
}