@article{03734456,
title = {Generalization of sum representation functional equations. I.},
journal = {International Journal of Mathematics and Mathematical Sciences},
volume = {2},
year = {1979},
pages = {459-471},
doi = {10.1155/S0161171279000351},
zbl = {0468.39006},
language = {en},
url = {http://dml.mathdoc.fr/item/03734456}
}
Kannappan, P.L.; Sathyabhama, V. Generalization of sum representation functional equations. I.. International Journal of Mathematics and Mathematical Sciences, Tome 2 (1979) pp. 459-471. doi : 10.1155/S0161171279000351. http://gdmltest.u-ga.fr/item/03734456/