@article{MZM_1973_13_1_a17,
     author = {R. M. Min'kova},
     title = {Korovkin systems for operators of class $S_m$},
     journal = {Matemati\v{c}eskie zametki},
     pages = {147--158},
     publisher = {mathdoc},
     volume = {13},
     number = {1},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1973_13_1_a17/}
}