%0 Journal Article
%A David E. Dobbs
%T A characterization of the tangent function.
%J Elemente der Mathematik
%D 1989
%P 101-104
%V 44
%N 3
%I mathdoc
%U http://geodesic.mathdoc.fr/item/ELMA_1989__44_3_141460/
%F ELMA_1989__44_3_141460