@article{AM2_1978__17_136739,
     author = {Marek Kuczma},
     title = {On some alternative functional equations.},
     journal = {Aequationes mathematicae},
     pages = {182--198},
     publisher = {mathdoc},
     volume = {17},
     year = {1978},
     zbl = {0398.39007},
     url = {http://geodesic.mathdoc.fr/item/AM2_1978__17_136739/}
}