@article{GDZPPN00208323X, title = {Why Means in Two Arguments are Special.}, journal = {Elemente der Mathematik}, volume = {49}, year = {1994}, pages = {32-37}, zbl = {0860.26014}, url = {http://dml.mathdoc.fr/item/GDZPPN00208323X} }
Lorenzen, Gunter. Why Means in Two Arguments are Special.. Elemente der Mathematik, Tome 49 (1994) pp. 32-37. http://gdmltest.u-ga.fr/item/GDZPPN00208323X/