Literatur / References:
P. G. Bergmann. Introduction to the Theory of Relativity. Dover Publications, 1976.
R. M. Wald. General Relativity, The University of Chicago Press, 1984.
E. Witten. A new proof of the positive energy theorem. Communications in Mathematical Physics. 80.3 (1981): 381-402.
R. Bartnik. The mass of an asymptotically flat manifold. Communications on pure and applied mathematics 39.5 (1986): 661-693.