Oscillations of the F(R) dark energy in the accelerating universe E. Elizalde, S.D. Odintsov, L. Sebastiani and S. Zerbini Eur. Phys. J. C, 72 2 (2012) 1843 Published online: 03 February 2012 DOI: 10.1140/epjc/s10052-011-1843-7