@article{DAN_1972_206_2_a0,
     author = {A. V. Arkhangel'skii},
     title = {The frequency spectrum of a topological space and the classification of spaces},
     journal = {Doklady Akademii Nauk},
     pages = {265--268},
     publisher = {mathdoc},
     volume = {206},
     number = {2},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1972_206_2_a0/}
}