References
- Global Lorentzian Geometry Beem, J.K.;Ehrlich, P.E.;Easely, K.L.
- Einstein Manifolds Besse, A.L.
- Trans. Amer. Math. Soc. v.145 Manifolds of negative curvature Bishop, R.;O'Neill, B.
- Eigenvalues in Riemannian Geometry Chavel, I.
- Local existence of warped product metrics Easely, K.L.
- Tensor, N.S. v.52 On Einstein Warped products Gebarowski, A.
- Semi-Riemannian Geometry O'Neill, B.