2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/42192It is reviewed pedagogically how a very successful description of the eta-eta' mass matrix can be achieved in the consistently coupled Schwinger-Dyson and Bethe-Salpeter approach in spite of the limitations of the ladder approximation. This description is in agreement with both phenomenology and lattice results.Talk at the Mini-Workshop "Quarks and Hadrons", 7-14 July 2002, Bled, Slovenia, uses their proceedings LaTeX style, 7 pagesHigh Energy Physics - PhenomenologyNuclear Theorytext