@article{DAN_1979_247_4_a1,
     author = {A. V. Arkhangel'skii},
     title = {Cardinal invariants of topological groups. {Imbeddings} and condensations},
     journal = {Doklady Akademii Nauk},
     pages = {779--782},
     publisher = {mathdoc},
     volume = {247},
     number = {4},
     year = {1979},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1979_247_4_a1/}
}