@article{MZM_1976_20_5_a19,
     author = {A. D. Gadzhiev},
     title = {Theorems of {Korovkin} type},
     journal = {Matemati\v{c}eskie zametki},
     pages = {781--786},
     year = {1976},
     volume = {20},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1976_20_5_a19/}
}