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
est unc	estimated uncertainty
Kaufman 1969	V. Kaufman and L. J. Radziemski Jr., J. opt. Soc. Amer. 59, 227-228 (1969) Redetermined Level Values and Interaction Parameters of S I and Cl II Ground Configurations
Jakobsson 1967	L. R. Jakobsson, Ark. Fys. (Stockholm) 34, 19-31 (1967) The Infrared Spectrum of the Neutral Sulfur Atom