@article{AM2_1977__15_136646,
     author = {Roman Ger},
     title = {On an alternative functional equation.},
     journal = {Aequationes mathematicae},
     pages = {145--162},
     year = {1977},
     volume = {15},
     zbl = {0361.39005},
     url = {http://geodesic.mathdoc.fr/item/AM2_1977__15_136646/}
}