Dirac, P. A. M. (1928). “The Quantum Theory of the Electron”. 《Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences》 117 (778): 610–624. doi:10.1098/rspa.1928.0023.
Dirac, P. A. M. (1930). “A Theory of Electrons and Protons”. 《Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences》 126 (801): 360–365. doi:10.1098/rspa.1930.0013.