@article{IVM_1971_6_a2,
     author = {B. G. Gabdulkhaev},
     title = {Certain questions of the theory of approximate {methods.~IV}},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {15--23},
     publisher = {mathdoc},
     number = {6},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1971_6_a2/}
}