2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/44521It is shown that the efficient mass formula we found for charged leptons in 1992 can be considered as an excellent approximate solution to the mysterious charged-lepton mass equation proposed by Koide in 1981.1+3 pages, LaTeX, no figuresHigh Energy Physics - Phenomenologytext