The 1D Hubbard model within the Composite Operator Method A. Avella, F. Mancini and M.d.M. Sánchez-López Eur. Phys. J. B, 29 3 (2002) 399-417 Published online: 14 October 2002 DOI: 10.1140/epjb/e2002-00323-6