1. These are not universal names, See H. R. Reiss, Phys. Rev. A 19, 1140 (1979); PLRAAN1050-2947
2. C. Leubner, Am. J. Phys. 49, 738 (1981). AJPIAS0002-9505
3. For further discussion on this gauge, see D. H. Kobe, Am. J. Phys. 50, 128 (1982).AJPIAS0002-9505
4. D. Bohm, Quantum Mechanics (Prentice‐Hall, Englewood Cliffs, 1951);
5. C. Cohen‐Tannoudji, B. Diu, and F. Laloë, Quantum Mechanics (Hermann/Wiley, Paris, 1977).