Reference Label	Details
Moore 1970	C. E. Moore, "Ionization Potentials and Ionization Limits Derived from Analyses of Optical Spectra", NSRDS-NBS 34, National Bureau of Standards: Washington, DC 1970
Edlen 1964	B. Edlén, in: Spectroscopy I / Spektroskopie I, S. Flügge, Ed., Hand. Phys. Encycl. Phys. 5/27, 80-220 (1964); Springer: Berlin, Heidelberg 1964 Atomic Spectra