@article{AM2_1991__42_3_137434,
     author = {Luigi Paganoni and Gian Luigi Forti},
     title = {On an alternative {Cauchy} equation in two unknown functions. {Some} classes of solutions.},
     journal = {Aequationes mathematicae},
     pages = {271--295},
     publisher = {mathdoc},
     volume = {42},
     number = {3},
     year = {1991},
     zbl = {0739.39009},
     url = {http://geodesic.mathdoc.fr/item/AM2_1991__42_3_137434/}
}