2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/66210We produce a new general family of flat tori in R^4, the first one since Bianchi's classical works in the 19th century. To construct these flat tori, obtained via small perturbation of certain Hopf tori in S^3, we first present a global description of all isometric immersions of R^2 into R^4 with flat normal bundle.26 pages, 1 figureDifferential Geometry53C40text