@article{DAN_1960_132_3_a5,
     author = {S. G. Krein},
     title = {On the notion of normal space scale},
     journal = {Doklady Akademii Nauk},
     pages = {510--513},
     publisher = {mathdoc},
     volume = {132},
     number = {3},
     year = {1960},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1960_132_3_a5/}
}