We consider closed topological 4-manifolds M with universal cover
S2ΓS2 and Euler characteristic Ο(M)=1. All such manifolds
with Ο=Ο1β(M)β Z/4 are homotopy equivalent. In this case,
we show that there are four homeomorphism types, and propose a candidate for a
smooth example which is not homeomorphic to the geometric quotient. If
Οβ Z/2ΓZ/2, we show that there are three
homotopy types (and between 6 and 24 homeomorphism types).Comment: 18 page