@article{MZM_1990_48_3_a11,
     author = {G. G. Magaril-Il'yaev},
     title = {Exact solutions of some approximation problems by means of positive operators},
     journal = {Matemati\v{c}eskie zametki},
     pages = {91--99},
     publisher = {mathdoc},
     volume = {48},
     number = {3},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1990_48_3_a11/}
}