@article{PORMA_1989__46_4_115681,
     author = {Cao, Jia-Ding and Gonska, Heinz H.},
     title = {Pointwise estimates for modified positive linear operators},
     journal = {Portugaliae mathematica},
     pages = {401--430},
     publisher = {mathdoc},
     volume = {46},
     number = {4},
     year = {1989},
     mrnumber = {1032511},
     zbl = {0683.41031},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1989__46_4_115681/}
}