%0 Journal Article %A John S. Lew %T A functional equation of Ih-Ching Hsu. %J Aequationes mathematicae %D 1989 %P 146-154 %V 38 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/item/AM2_1989__38_1_137322/ %F AM2_1989__38_1_137322