@article{AM2_1993__45_2-3_137519,
     author = {Fulvia Skof},
     title = {On two conditional forms of the equation ||f(x + y)|| = ||f(x) + f(y)||.},
     journal = {Aequationes mathematicae},
     pages = {167--178},
     publisher = {mathdoc},
     volume = {45},
     number = {2-3},
     year = {1993},
     zbl = {0776.39003},
     url = {http://geodesic.mathdoc.fr/item/AM2_1993__45_2-3_137519/}
}