@article{MZ_1960__74_169872,
     author = {Erich Kamke},
     title = {Zur {Theorie} der elementaren {Mittel.}},
     journal = {Mathematische Zeitschrift},
     pages = {91--98},
     publisher = {mathdoc},
     volume = {74},
     year = {1960},
     zbl = {0095.03801},
     url = {http://geodesic.mathdoc.fr/item/MZ_1960__74_169872/}
}