@article{MZM_1973_13_6_a0,
     author = {V. A. Baskakov},
     title = {The generalization of some theorems of {P.} {P.~Korovkin} on positive operators},
     journal = {Matemati\v{c}eskie zametki},
     pages = {785--794},
     year = {1973},
     volume = {13},
     number = {6},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1973_13_6_a0/}
}