2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/77707Let X be a scroll over a rational surface. We construct a linear system of surfaces in P^3 yielding a birational map from P^3 to X. We apply this construction to the scrolls of Bordiga and Palatini.14 pages, Plain-TeX, to be published in Collectanea MathematicaAlgebraic Geometry14C20, 14J30, 14M07, 14M20text