@article{DAN_1971_198_3_a6,
     author = {E. G. D'yakonov},
     title = {On approximate methods for the solution of operator equations},
     journal = {Doklady Akademii Nauk},
     pages = {516--519},
     publisher = {mathdoc},
     volume = {198},
     number = {3},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1971_198_3_a6/}
}