1. S. Alexakis, Unique continuation for the vacuum Einstein equations, preprint (2008); arXiv:0902.1131
2. S. Alexakis, A.D. Ionescu, S. Klainerman, Uniqueness of smooth stationary black holes in vacuum: small perturbations of the Kerr spaces, arXiv:0902.1173
3. Biquard O.: Continuation unique à partir de l’infini conforme pour les métriques d’einstein. Math. Res. Lett. 15, 1091–1099 (2008)
4. G.L. Bunting, Proof of the Uniqueness Conjecture for Black Holes, PhD Thesis, Univ. of New England, Armidale, NSW (1983).
5. Carter B.: Axisymmetric black hole has only two degrees of freedom. Phys. Rev. Letters 26, 331–333 (1971)