@article{GDZPPN002042215,
title = {On trigonometric functional equations of rectangular type.},
journal = {Aequationes mathematicae},
volume = {53},
year = {1997},
pages = {36-53},
zbl = {0901.39007},
url = {http://dml.mathdoc.fr/item/GDZPPN002042215}
}
Sahoo, P.K.; Chung, J.; Kannappan, P. On trigonometric functional equations of rectangular type.. Aequationes mathematicae, Tome 53 (1997) pp. 36-53. http://gdmltest.u-ga.fr/item/GDZPPN002042215/