Trapped surfaces in the Schwarzschild geometry and cosmic censorship.

@article{Wald1991TrappedSI,
  title={Trapped surfaces in the Schwarzschild geometry and cosmic censorship.},
  author={Wald and S Purushothaman Iyer},
  journal={Physical review. D, Particles and fields},
  year={1991},
  volume={44 12},
  pages={R3719-R3722}
}