@article{MZM_1975_17_3_a15,
     author = {O. A. Ziza},
     title = {On subsystems of systems of sets},
     journal = {Matemati\v{c}eskie zametki},
     pages = {485--495},
     publisher = {mathdoc},
     volume = {17},
     number = {3},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1975_17_3_a15/}
}