@article{DAN_1970_191_3_a0,
     author = {A. D. Aleksandrov},
     title = {Mappings of families of sets},
     journal = {Doklady Akademii Nauk},
     pages = {503--506},
     publisher = {mathdoc},
     volume = {191},
     number = {3},
     year = {1970},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1970_191_3_a0/}
}