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
Pekeris 1958	C. L. Pekeris, Phys. Rev. 112, 1649-1658 (1958) Ground State of Two-Electron Atoms
Pekeris 1962	C. L. Pekeris, Phys. Rev. 126, 1470-1476 (1962) 1 1S, 2 1S, and 2 3S States of H- and of He
est unc	estimated uncertainty