1. P.A.M. Dirac, The Lagrangian in quantum mechanics. Phys. Z. Sowjetunion 3, 64 (1933)
2. P.A.M. Dirac, The Principles of Quantum Mechanics (Oxford University Press, London, 1947)
3. N. Wiener, Differential space. J. Math. Phys. Sci. 2, 132 (1923)
4. R. Feynman, Spacetime approach to non-relativistic quantum mechanics. Rev. Mod. Phys. 20, 267 (1948)
5. R. Feynman, A. Hibbs, Quantum Mechanics and Path Integrals (Dover, New York, 2010)