Granovsky, Alexander A. (7 June 2011). "Extended multi-configuration quasi-degenerate perturbation theory: The new approach to multi-state multi-reference perturbation theory". The Journal of Chemical Physics. 134 (21): 214113. Bibcode:2011JChPh.134u4113G. doi:10.1063/1.3596699. PMID21663350.
Granovsky, Alexander A. (7 June 2011). "Extended multi-configuration quasi-degenerate perturbation theory: The new approach to multi-state multi-reference perturbation theory". The Journal of Chemical Physics. 134 (21): 214113. Bibcode:2011JChPh.134u4113G. doi:10.1063/1.3596699. PMID21663350.
Granovsky, Alexander A. (7 June 2011). "Extended multi-configuration quasi-degenerate perturbation theory: The new approach to multi-state multi-reference perturbation theory". The Journal of Chemical Physics. 134 (21): 214113. Bibcode:2011JChPh.134u4113G. doi:10.1063/1.3596699. PMID21663350.