SEARCH Articles Figures Tables Brillouin-Wigner (BW) and Rayleigh-Schrodinger (RS) expansions Brillouin-Wigner configuration interaction expansions Brillouin-Wigner coupled cluster expansions Multireference Brillouin-Wigner configuration interaction expansions Perturbation expansions Brillouin-Wigner Single reference Brillouin-Wigner expansions