@article{ZVMMF_1984_24_12_a14,
     author = {A. V. Karzanov},
     title = {Closed sets of a directed graph},
     journal = {\v{Z}urnal vy\v{c}islitelʹnoj matematiki i matemati\v{c}eskoj fiziki},
     pages = {1903--1906},
     publisher = {mathdoc},
     volume = {24},
     number = {12},
     year = {1984},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZVMMF_1984_24_12_a14/}
}