Pierson, E., Beuken, J.-M., & Bertrand, P. (1990). Computer-simulation of Reionization in Iss. Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms, 45(1-4), 374-379. https://doi.org/10.1016/0168-583X(90)90855-O (Original work published 1990)