Ab initio cluster calculations of Co3+ spin states in RBaCo2O5.5 (R = Ho, Gd) L. Siurakshina, B. Paulus and V. Yushankhai Eur. Phys. J. B, 63 4 (2008) 445-450 Published online: 10 July 2008 DOI: 10.1140/epjb/e2008-00263-1