@article{ZNSL_1998_255_a2,
     author = {O. L. Vinogradov},
     title = {The sharp constant in {Jackson-type} inequality for approximation by linear positive operators},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {36--53},
     publisher = {mathdoc},
     volume = {255},
     year = {1998},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1998_255_a2/}
}