@article{10_4064_ap_21_1_39_46,
     author = {M. Kuczma},
     title = {On a new characterization of the exponential functions},
     journal = {Annales Polonici Mathematici},
     pages = {39--46},
     publisher = {mathdoc},
     volume = {21},
     number = {1},
     year = {1968},
     doi = {10.4064/ap-21-1-39-46},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/ap-21-1-39-46/}
}