2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/49448We briefly introduce the Wick-contraction parametrization of hadronic matrix elements and discuss some applications to B and K physics.LaTeX2e, 6 pages, 1 eps figure included. Invited talk at KAON `99, June 21-26, 1999, Chicago IL, USAHigh Energy Physics - Phenomenologytext