Exact $f(R)$-cosmological model coming from the request of the existence   of a Noether symmetry
  We present an $f(R)$-cosmological model with an exact analytic solution, coming from the request of the existence of a Noether symmetry, which is able to describe a dust-dominated decelerated phase before the current accelerated phase of the universe. 
S. Capozziello, P. Martin-Moruno and C. Rubano