Dirac, P. A. M. (1925). "The Fundamental Equations of Quantum Mechanics". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences. 109 (752): 642. Bibcode:1925RSPSA.109..642D. doi:10.1098/rspa.1925.0150.
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Dirac, P. A. M. (1925). "The Fundamental Equations of Quantum Mechanics". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences. 109 (752): 642. Bibcode:1925RSPSA.109..642D. doi:10.1098/rspa.1925.0150.