2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/39334Discussed is the structure of non-trivial counterterms that occur in the systematic gauge-invariant perturbation theory with unstable fields introduced in [hep-ph/9802307].4pp PS; talk at QFTHEP'99, 27 May - 2 June 1999, MoscowHigh Energy Physics - PhenomenologyHigh Energy Physics - TheoryMathematical Physicstext