@article{DAN_1974_218_5_a0,
     author = {A. D. Gadzhiev},
     title = {The convergence problem for a sequence of positive linear operators on unbounded sets, and theorems analogous to that of {P.\,P.~Korovkin}},
     journal = {Doklady Akademii Nauk},
     pages = {1001--1004},
     publisher = {mathdoc},
     volume = {218},
     number = {5},
     year = {1974},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1974_218_5_a0/}
}