1. Breakdown of predictability in gravitational collapse
2. Wormholes in spacetime;Hawking,1987
3. S.B. Giddings and A. Strominger, Axion-induced topology change in quantum gravity and string theory, HUTP-87/ A067.
4. Quantum coherence down the wormhole
5. S. Coleman, Black holes as red herrings: Topological fluctuations and the loss of quantum coherence, Harvard preprint HUTP-88/A008.