Direct overlapping effect of f orbitals for valence fluctuating materials in Kondo regime H. A. Razafimandimby, D. Randrianasoloharisoa, A. Rakotomahevitra and J. C. Parlebas Eur. Phys. J. B, 68 4 (2009) 495-500 Published online: 01 April 2009 DOI: 10.1140/epjb/e2009-00118-3