@article{GDZPPN002022494, title = {\"Uber die Funktionalgleichung f (1 + x) + f (1 + f (x)) = 1.}, journal = {Aequationes mathematicae}, volume = {1}, year = {1968}, pages = {267-274}, zbl = {0165.17201}, url = {http://dml.mathdoc.fr/item/GDZPPN002022494} }
Benz, W.; Elliger, S. Über die Funktionalgleichung f (1 + x) + f (1 + f (x)) = 1.. Aequationes mathematicae, Tome 1 (1968) pp. 267-274. http://gdmltest.u-ga.fr/item/GDZPPN002022494/