@article{MM2_1976__18_154399,
     author = {J\"urgen Spilker and Jean Dhombres},
     title = {\"Uber die {Funktionalgleichung} f(f(x) * f(y)) = f(x*y).},
     journal = {Manuscripta mathematica},
     pages = {371--390},
     publisher = {mathdoc},
     volume = {18},
     year = {1976},
     zbl = {0335.39005},
     url = {http://geodesic.mathdoc.fr/item/MM2_1976__18_154399/}
}