@article{GDZPPN002037904,
title = {On two mean value properties and functional equations associated with them.},
journal = {Aequationes mathematicae},
volume = {38},
year = {1989},
pages = {216-235},
zbl = {0688.39006},
url = {http://dml.mathdoc.fr/item/GDZPPN002037904}
}
Aczél, János; Kuczma, Marek. On two mean value properties and functional equations associated with them.. Aequationes mathematicae, Tome 38 (1989) pp. 216-235. http://gdmltest.u-ga.fr/item/GDZPPN002037904/