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