1. Birkhoff, George D. 1923. Relativity and Modern Physics, Cambridge. Mass.: Harvard University Press.
2. Cartan, Élie. 1974. Notice sur les travaux scientifiques. Paris: Gauthier-Villars.
3. CPAE 5. 1993. Collected Papers of Albert Einstein, Vol. 5: The Swiss Years: Correspondence, 1902–1914, Martin J. Klein, et al., eds., Princeton: Princeton University Press.
4. CPAE 7. 2002. Collected Papers of Albert Einstein, Vol. 7: The Berlin Years: Writings, 1918–1921, Michel Janssen, et al., eds., Princeton: Princeton University Press.
5. CPAE 8A. 1998a. Collected Papers of Albert Einstein, Vol. 8A: The Berlin Years: Correspondence, 1914–1917, Robert Schulmann, et al., eds., Princeton: Princeton University Press.