@article{MAN_1977__229_163004,
     author = {G. Leha},
     title = {Relative {Korovkin-S\"atze} und {R\"ander.}},
     journal = {Mathematische Annalen},
     pages = {87--95},
     publisher = {mathdoc},
     volume = {229},
     year = {1977},
     zbl = {0337.41032},
     url = {http://geodesic.mathdoc.fr/item/MAN_1977__229_163004/}
}