2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/169206A glossary overview of the phenomenological studies of quasi-realistic free fermionic heterotic string models is presented. I elaborate on the correspondence of these models with Z2XZ2 orbifolds.14 pages. Standard LaTexHigh Energy Physics - TheoryHigh Energy Physics - Phenomenologytext