@article{ELMA_1966__21_140819,
     author = {J\"urg R\"atz},
     title = {Zur {Theorie} der {Funktionalgleichung} f(xy) = f(x) + f(y).},
     journal = {Elemente der Mathematik},
     pages = {10--13},
     publisher = {mathdoc},
     volume = {21},
     year = {1966},
     zbl = {0136.12402},
     url = {http://geodesic.mathdoc.fr/item/ELMA_1966__21_140819/}
}