TY  - JOUR
AU  - David E. Dobbs
TI  - A characterization of the tangent function.
JO  - Elemente der Mathematik
PY  - 1989
SP  - 101
EP  - 104
VL  - 44
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/ELMA_1989__44_3_141460/
ID  - ELMA_1989__44_3_141460
ER  -