  To a rational homology sphere graph manifold one can associate a weighted
tree invariant called splice diagram. In this article we prove a sufficient
numerical condition on the splice diagram for a graph manifold to be a
singularity link. We also show that if two manifolds have the same splice
diagram, then their universal abelian covers are homeomorphic. To prove the
last theorem we have to generalize our notions to orbifolds.

Geometric Topology