This series draws from several sources. In particular: Einstein et al, The Principle of Relativity, Dover Publications, 1952, ISBN 978-0486600819; Dirac, General Theory of Relativity, Princeton, 1996, ISBN: 0-691-01146-X; Taylor and Wheeler, Exploring Black Holes, 2000, ISBN 0-201-38423-X; and Misner, Thorne and Wheeler, Gravitation, Freeman, 1973, ISBN 0-7167-0344-0.
