TY  - JOUR
AU  - Frank Forelli
TI  - Two-sheeted coverings of the disc.
JO  - Mathematica Scandinavica
PY  - 1987
SP  - 17
EP  - 38
VL  - 61
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MS2_1987__61_2_186105/
ID  - MS2_1987__61_2_186105
ER  -