1. A mathematically rigorous modern proof of Pauli’s theorem, apart from many other related issues can be found in M. D. Srinivas and R. Vijayalakshmi, Time of ‘occurence’ in quantum mechanics. Pramana 16, 173 (1981)
2. Albert Einstein—Philosopher Scientist. The Library of Living Philosophers, vol. VII (P. A. Schilpp, New York 1969). Contribution by Niels Bohr
3. This is a well known result. See for example, section 1.3 in P. Sharan, Spacetime, Geometry and Gravitation (Birkhauser, Basel, 2009)
4. L. Mandelstam, I.G. Tamm, J. Phys. USSR, 9, 249 (1945)
5. V. Fock, N. Krylov, Uncertainty relation between time and energy. J. Phys. USSR 11, 112 (1947)