Relativity Reexamined

• Léon Brillouin : Relativity Reexamined (PDF)
• Mass-energy equivalence, especially: 9.5.2 Alternative version
• Cannon on a railroad car / Newtonian derivation of   E = m c²
• The Limited Validity of Special Relativity
  Albert Einstein's Gedanken-Experimente
  reexamined for small masses
• Immortal Fumbles by Dirk van de Moortel
• Einstein's Gravitational Metrics
• Einstein online - Home
• Conspiracy of Light
• Excellent Math Pages, especially Reflections on Relativity.
  Absorbed:
  • 6.3. Bending Light
  • Gerber's Gravity
• The Black Hole, the Big Bang, and Modern Physics
  website by Stephen J. Crothers has nice references:
  • On the Gravitational Field of a Mass Point
    according to Einstein’s Theory
    by K. Schwarzschild
  • On the Gravitational Field of a Sphere of Incompressible Fluid
    according to Einstein’s Theory
    by K. Schwarzschild
  • Mechanics. - On the analytic expression that must be given
    to the gravitational tensor in Einstein’s theory
    Note by the Fellow T. Levi-Civita