2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/209238The cosmological background of gravitational waves can be tuned by Extended Theories of Gravity. In particular, it can be shown that assuming a generic function f(R) of the Ricci scalar R gives a parametric approach to control the evolution and the production mechanism of gravitational waves in the early Universe.4 Pages, in "Problems of Modern Cosmology" for the 50th bithday of S.D. OdintsovGeneral Relativity and Quantum Cosmologytext