@article{MZM_1976_20_4_a3,
     author = {E. G. Pytkeev},
     title = {Upper bounds of topologies},
     journal = {Matemati\v{c}eskie zametki},
     pages = {489--500},
     year = {1976},
     volume = {20},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1976_20_4_a3/}
}