2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/48938In this contribution recent developments are discussed which lead to a significant reduction of the error for $α(M_Z^2)$ and $(g-2)_μ$.6 pages, Talk presented at the 17th International Workshop on Weak Interactions and Neutrinos (WIN99), Cape Town, South Africa, January 24--30, 1999High Energy Physics - Phenomenologytext