We consider cosmological dynamics in fourth order gravity with both f(R)
and Φ(G) correction to the Einstein gravity (G is
the Gauss-Bonnet term). The particular case for which both terms are equally
important on power-law solutions is described. These solutions and their
stability are studied using the dynamical system approach. We also discuss
condition of existence and stability of de Sitter solution in a more general
situation of power-law f and Φ.Comment: published version, references update