@article{KUKTF_1985_5_5_a1,
     author = {B. G. Gabdulkhaev},
     title = {Approximate numbers of linear operators and optimization of approximate methods for solving functional equations},
     journal = {Konstruktivnaya Teoriya Funktsii i Funktsional'nyi Analiz},
     pages = {15--26},
     year = {1985},
     volume = {5},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/KUKTF_1985_5_5_a1/}
}