Reinstating Schwarzschild's original manifold and its singularity
  The content of this review is summarized here through the titles of its sections, as follows:   1. Introduction: Schwarzschild's original solution and the ``Schwarzschild solution''.   2. The wrong arrow of time of Hilbert's manifold is at the origin of the Kruskal extension.   3. An invariant, local, intrinsic quantity that diverges at the Schwarzschild surface.   4. The singularity at the Schwarzschild surface is both intrinsic and physical.   5. Conclusion. 
Salvatore Antoci, Dierck-Ekkehard Liebscher