@article{GDZPPN002550326, title = {On a functional equation arising from hyperbolic geometry.}, journal = {Aequationes mathematicae}, volume = {20}, year = {1980}, pages = {113-119}, zbl = {0443.39005}, url = {http://dml.mathdoc.fr/item/GDZPPN002550326} }
Benz, Walter. On a functional equation arising from hyperbolic geometry.. Aequationes mathematicae, Tome 20 (1980) pp. 113-119. http://gdmltest.u-ga.fr/item/GDZPPN002550326/