@article{DAN_1974_218_5_a8,
     author = {G. V. Chudnovskii and D. V. Chudnovskii},
     title = {Descendingly incomplete ultrafilters},
     journal = {Doklady Akademii Nauk},
     pages = {1032--1035},
     publisher = {mathdoc},
     volume = {218},
     number = {5},
     year = {1974},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1974_218_5_a8/}
}