TY  - JOUR
AU  - H.G. HELFENSTEIN
TI  - On the Distortion of Conformal Immersions between 2-Space Forms.
JO  - Mathematische Annalen
PY  - 1969
SP  - 159
EP  - 168
VL  - 183
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MAN_1969__183_161887/
ID  - MAN_1969__183_161887
ER  -