@article{VUU_2011_3_a1,
     author = {E. S. Bastrykov},
     title = {On closures of countable subsets of~$BN$},
     journal = {Vestnik Udmurtskogo universiteta. Matematika, mehanika, kompʹ\^uternye nauki},
     pages = {15--20},
     year = {2011},
     number = {3},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VUU_2011_3_a1/}
}