  A modification of the action of the general relativity produces a different
pattern for the growth of the cosmic structures below a certain length-scale
leaving an imprint on the cosmic microwave background (CMB) anisotropies. We
re-examine the upper limits on the length-scale parameter B0 of f (R) models
using the recent data from the Planck satellite experiment. We also investigate
the combined constraints obtained when including the Hubble Space Telescope H0
measurement and the baryon acoustic oscillations measurements from the SDSS,
WiggleZ and BOSS surveys.
