@article{MZ_1979__168_172874,
     author = {Heinz Bauer and G. Leha and S. Papadopoulou},
     title = {Determination of {Korovkin} {Closures.}},
     journal = {Mathematische Zeitschrift},
     pages = {263--274},
     publisher = {mathdoc},
     volume = {168},
     year = {1979},
     zbl = {0393.46027},
     url = {http://geodesic.mathdoc.fr/item/MZ_1979__168_172874/}
}