Fourth-order perturbation theory for the half-filled Hubbard model in infinite dimensionsF. Gebhard, E. Jeckelmann, S. Mahlert, S. Nishimoto and R. M. NoackEur. Phys. J. B, 36 4 (2003) 491-509DOI: https://doi.org/10.1140/epjb/e2004-00005-5