@article{GDZPPN002030004, title = {\"Uber die Funktionalgleichung f(f(x)*f(y)) = f(x*y). (Short Communication).}, journal = {Aequationes mathematicae}, volume = {15}, year = {1977}, pages = {112-113}, zbl = {0335.39005}, url = {http://dml.mathdoc.fr/item/GDZPPN002030004} }
Spilker, J.; Dhombres, J. Über die Funktionalgleichung f(f(x)*f(y)) = f(x*y). (Short Communication).. Aequationes mathematicae, Tome 15 (1977) pp. 112-113. http://gdmltest.u-ga.fr/item/GDZPPN002030004/