TY  - JOUR
AU  - Jörg Waldvogel
TI  - The Problem of the Circular Billiard.
JO  - Elemente der Mathematik
PY  - 1992
SP  - 108
EP  - 113
VL  - 47
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/ELMA_1992__47_3_141532/
ID  - ELMA_1992__47_3_141532
ER  -