Parr, Robert G.; Craig D. P.; Ross, I. G (1950). "Molecular Orbital Calculations of the Lower Excited Electronic Levels of Benzene, Configuration Interaction included". Journal of Chemical Physics. 18 (12): 1561–1563. Bibcode:1950JChPh..18.1561P. doi:10.1063/1.1747540.
Parr, Robert G.; Craig D. P.; Ross, I. G (1950). "Molecular Orbital Calculations of the Lower Excited Electronic Levels of Benzene, Configuration Interaction included". Journal of Chemical Physics. 18 (12): 1561–1563. Bibcode:1950JChPh..18.1561P. doi:10.1063/1.1747540.