@article{UZKU_1968_128_5_a1,
     author = {B. G. Gabdulkhaev},
     title = {Certain questions of approximate methods},
     journal = {U\v{c}\"enye zapiski Kazanskogo universiteta. Seri\^a Fiziko-matemati\v{c}eskie nauki},
     pages = {20--29},
     publisher = {mathdoc},
     volume = {128},
     number = {5},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/UZKU_1968_128_5_a1/}
}