TY  - JOUR
AU  - Fr. Fabricius-Bjerre
TI  - On the Double Tangents of Plane Closed Curves.
JO  - Mathematica Scandinavica
PY  - 1962
SP  - 113
EP  - 116
VL  - 11
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MS2_1962__11_165818/
ID  - MS2_1962__11_165818
ER  -