2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/94087The Klein paradox of Klein-Gordon (KG) equation is discussed to show that KG equation is self-consistent even at one-particle level and the wave function for antiparticle is uniquely determined by the reasonable explanation of Klein paradox. No concept of ``hole'' is needed.4 pages, no figures, revtexQuantum Physicstext