SEARCH Articles Figures Tables Brillouin-Wigner (BW) and Rayleigh-Schrodinger (RS) expansions Brillouin-Wigner coupled cluster singles and Brillouin-Wigner perturbation theory and limited configuration interaction Comparison of Brillouin-Wigner and Rayleigh-Schrodinger perturbation theories Coupled cluster single- and doubleexcitations approximation Brillouin-Wigner Matrix Elements and the Wigner-Eckart Theorem Multi-reference Brillouin-Wigner coupled cluster single- and Non-adiabatic coupling Wigner rotation matrix and Von Neumann and Wigner Wigner and Verwey Transitions