Zyla, P.A.; et al. (Particle Data Group) (2020). "Review of Particle Physics"(PDF). Progress of Theoretical and Experimental Physics: Neutral Heavy Leptons, Searches for. 2020 (8): 083C01 [1168]. doi:10.1093/ptep/ptaa104.
Zyla, P.A.; et al. (Particle Data Group) (2020). "Review of Particle Physics"(PDF). Progress of Theoretical and Experimental Physics: Neutral Heavy Leptons, Searches for. 2020 (8): 083C01 [1168]. doi:10.1093/ptep/ptaa104.