2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/164302We present a brief description of the recently developed Fortran code TERAD91 for semi-analytical calculations of the double differential cross sections of NC and CC deep inelastic electron-proton scattering and of some related observables. The code is mainly intended for the calculations at HERA or other ep-colliders but may be also used for similar processes like muon-proton scattering in fixed-target experiments.9 pages, Talk given at the DESY Workshop "PHYSICS at HERA", Hamburg, Germany, 29-30 October, 1991High Energy Physics - Phenomenologytext