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
Persson 1968	W. Persson and L. Minnhagen, Ark. Fys. 37, 273-300 (1968)
Bowen 1955	I. S. Bowen, Astrophys. J. 121, 306-311 (1955) Wave Lengths of Forbidden Nebular Lines
Edlen 1964	B. Edlén, Handb. Phys. Encycl. Phys. 27, 80-220 (1964) Atomic Spectra Note: Springer: Berlin 1964