@article{DAN_1967_173_1_a9,
     author = {Yu. I. Petunin},
     title = {Prenuclear mappings in scales of {Banach} and {Hilbert} spaces},
     journal = {Doklady Akademii Nauk},
     pages = {40--43},
     year = {1967},
     volume = {173},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1967_173_1_a9/}
}