@article{MZ_1934__38_168495,
     author = {K.T'. L\"owner},
     title = {\"Uber monotone {Matrixfunktionen}},
     journal = {Mathematische Zeitschrift},
     pages = {177--216},
     publisher = {mathdoc},
     volume = {38},
     year = {1934},
     url = {http://geodesic.mathdoc.fr/item/MZ_1934__38_168495/}
}