SEARCH Articles Figures Tables Brillouin-Wigner perturbation Brillouin-Wigner perturbation theory Brillouin-Wigner perturbation theory Rayleigh-Schrodinger Brillouin-Wigner theory Comparison of Theories Perturbation theory Brillouin Perturbation theory Schrodinger Perturbation theory, Rayleigh-Schrodinge Rayleigh theory Rayleigh-Schrodinger Rayleigh-Schrodinger perturbation Rayleigh-Schrodinger perturbation theory Rayleigh-Schrodinger theory Schrodinger theory Theory of perturbation Wigner and