A critical assessment of multireference-Fock space CCSD and perturbative third-order triples approximations for photoelectron spectra and quasidegenerate potential energy surfaces
De. Bernholdt et Rj. Barlett, A critical assessment of multireference-Fock space CCSD and perturbative third-order triples approximations for photoelectron spectra and quasidegenerate potential energy surfaces, ADV QUANT C, 34, 1999, pp. 271-293