Measurement of the Rate Coefficients for the Bimolecular and Termolecular Charge Transfer Reactions of He₂⁺ with Ne, Ar, N₂, CO, CO₂, and CH₄, dissertation, May 1977; (https://digital.library.unt.edu/ark:/67531/metadc331306/m1/1/: accessed July 17, 2024), University of North Texas Libraries, UNT Digital Library, digital.library.unt.edu; .