1. V. Sahni, Int. J. Quantum Chem. 121, e26556 (2021). (This is a representative work. The references to other original literature is provided as the theory is developed in the chapters to follow)
2. E. Schrödinger, Ann. Physik 79, 361, 489 (1925); 80, 437 (1926); 81, 109 (1926); E. Schrödinger, Collected Papers on Wave Mechanics, (American Mathematical Society Chelsea Publishing, Providence, Rhode Island, Reprinted 2014)
3. M.Born, Z. Physik 38, 803 (1926); W. Heisenberg, Z. Physik 43, 172 (1927); N. Bohr, Naturwis, 16, 245 (1928); 17, 483 (1929); 18, 73 (1930)
4. W. Pauli, Z. Physik 31, 765 (1925)
5. P.A.M. Dirac, Proc. Roy. Soc. A112, 661 (1926)