Adachi, I., Ahlburg, P., Aihara, H., Akopov, N., Aloisio, A., Ky, A., et al. (2020). Search for an Invisibly Decaying Z^ ' Boson at Belle II in e^ + e^ - →μ^ + μ^ - (e^ ± μ^ ∓ ) Plus Missing Energy Final States. Physical Review Letters, 124(14), 141801. https://doi.org/10.1103/PhysRevLett.124.141801 (Original work published 2020)