Observations have been made in the range 1200–2000A of the arc spectra of B, In, Tl, Pb, and Bi. The analysis of B I and Bi I has been considerably extended with the aid of these observations, while new levels been found in In I, Tl I, and Pb I.
H. E. CLEARMAN, "On the Arc Spectra of Boron, Indium, Thallium, Lead, and Bismuth," J. Opt. Soc. Am. 42, 373-376 (1952)