Fussen, D., Claeys, W., Cornet, A., Jureta, J., & Defrance, P. (1982). Absolute Total Cross-section Measurement of Ion-pair Production in H(1s)-h(2s) Collisions. Journal of Physics B: Atomic, Molecular and Optical Physics, 15(19), L715-L718. https://doi.org/10.1088/0022-3700/15/19/005 (Original work published 1982)