Reference Label	Details
Watanabe 1954	K. Watanabe, J. Chem. Phys. 22, 1564-1570 (1954) Photoionization and Total Absorption Cross Section of Gases. I. Ionization Potentials of Several Molecules. Cross Sections of NH3 and NO
Watanabe 1962	K. Watanabe, T. Nakayama, and J. Mottl, J. Quant. Spectrosc. Rad. Trans. 2, 369-382 (1962) Ionization Potentials of Some Molecules