@article{MZ_1984__186_173457,
     author = {Heinz H. Gonska},
     title = {Quantitative {Krovkin} {Type} {Theorems} on {Simultaneous} {Approximation.}},
     journal = {Mathematische Zeitschrift},
     pages = {419--434},
     publisher = {mathdoc},
     volume = {186},
     year = {1984},
     zbl = {0523.41013},
     url = {http://geodesic.mathdoc.fr/item/MZ_1984__186_173457/}
}