@article{DAN_1965_163_4_a8,
     author = {L. V. Ovsyannikov},
     title = {Singular operator in the scale of {Banach} spaces},
     journal = {Doklady Akademii Nauk},
     pages = {819--822},
     year = {1965},
     volume = {163},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1965_163_4_a8/}
}