@article{MS2_1980__47_166727,
     author = {Gunnar Sparr},
     title = {A new proof of {L\"owner's} theorem on monotone matrix functions.},
     journal = {Mathematica Scandinavica},
     pages = {266--274},
     publisher = {mathdoc},
     volume = {47},
     year = {1980},
     zbl = {0433.15012},
     url = {http://geodesic.mathdoc.fr/item/MS2_1980__47_166727/}
}