R. J. Bartlett and G. D. Purvis III, “Many-body perturbation-theory, coupled-pair many-electron theory, and importance of quadruple excitations for correlation problem,” Int. J. Quantum Chem., 14 (1978) 561-81. DOI: 10.1002/qua.560140504
R. J. Bartlett and G. D. Purvis III, “Many-body perturbation-theory, coupled-pair many-electron theory, and importance of quadruple excitations for correlation problem,” Int. J. Quantum Chem., 14 (1978) 561-81. DOI: 10.1002/qua.560140504
