@article{DAN_1979_245_3_a2,
     author = {I. I. Golichev},
     title = {Approximation of an element in the range of a function of an operator},
     journal = {Doklady Akademii Nauk},
     pages = {527--530},
     year = {1979},
     volume = {245},
     number = {3},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1979_245_3_a2/}
}