TY  - JOUR
AU  - John Hempel
TI  - Orientation Reversing Involutions and the First Betti Number for Finite Coverings of 3-Manifolds.
JO  - Inventiones mathematicae
PY  - 1982
SP  - 133
EP  - 142
VL  - 67
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/IM_1982__67_142904/
ID  - IM_1982__67_142904
ER  -