1. This high-school correspondence has been published in Alice Kimball Smith and Charles Weiner, Robert Oppenheimer: Letters and Recollections (Cambridge, Mass. and London: Harvard University Press, 1980), pp. 95–96, 113, 119–121, 126–127, 132–141.
2. P.A.M. Dirac, The Principles of Quantum Mechanics (Oxford: Clarendon Press, 1930).
3. E.T. Whittaker and G.N. Watson, A Course of Modern Analysis. Fourth Edition (Cambridge: Cambridge University Press, 1927).
4. Res Jost, The General Theory of Quantized Fields (Providence, R.I.: American Mathematical Society, 1965).
5. Harold C. Urey, F.G. Brickwedde, and G.M. Murphy, “A Hydrogen Isotope of Mass 2,” Physical Review 39 (1932), 164–165.