1. The Feynman Lectures on Physics: Quantum Mechanics;Feynman,1965
2. R.P. Feynman to F.J. Dyson, Private Communication: Concerned with his “Sum Over Histories” Version of Quantum Mechanics, 1949.
3. Equations of Mathematical Physics;Tikhonov,1990
4. W. Heisenberg to W. Pauli, Private Communication: Referred to the Physical Portion of Schrödinger’s Theory, 1926.
5. W. Heisenberg, Zeitschrift für Physik, 43 (1927) 172–198s(English translation: J. Archibald Wheeler, Hubert Zurek), in: Quantum Theory and Measurement, Princeton Univ. Press, Princeton, 1983, pp. 62–84.