TY  - JOUR
AU  - Friedrich Hegenbarth
AU  - Alberto Cavicchioli
TI  - On 4-manifolds with free fundamental group.
JO  - Forum mathematicum
PY  - 1994
SP  - 415
EP  - 430
VL  - 6
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/FORUM_1994__6_3_141746/
ID  - FORUM_1994__6_3_141746
ER  -