@article{DAN_1967_177_3_a7,
     author = {Bl. Sendov},
     title = {On the theorems of {P.\,P.~Korovkin} for convergence of sequences of linear positive operators},
     journal = {Doklady Akademii Nauk},
     pages = {518--520},
     publisher = {mathdoc},
     volume = {177},
     number = {3},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1967_177_3_a7/}
}