1. Sitzungsber. Preuss. Akad. Wiss. Berlin Math. Phys. 778, (1915).
2. Relativity, Thermodynamics and Cosmology, p. 227 (Oxford University Press, London, 1934).
3. and , The classical theory of fields (Pergamon Press, Oxford, 1987).
4. Spin and Angular Momentum in General Relativity