2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/79326We construct examples of non-projective normal proper algebraic surfaces and discuss the pathological behaviour of their Neron-Severi group. Our surfaces are birational to the product of a projective line and a curve of higher genus.7 pages, Latex2e, to be published in Manuscripta MathematicaAlgebraic Geometry14J05; 14J17text