1. P. K. Pearson, G. L. Blackman, H. F. Schaefer, B. Roos, and U. Wahlgren, Astrophys. J. Lett. 184, L19 (1973).
2. For example see, R. D. Brown and E. H. N. Rice, J. Am. Chem. Soc. 106, 6475 (1984).
3. T. Lee and G. Scuseria, see the chapter entitled “Achieving Chemical Accuracy with Coupled-Cluster Theory” in this volume.
4. M. Perić, B. Engels, and S. D. Peyerimhoff, see the chapter entitled “Theoretical Spectroscopy on Small Molecules: Ab initio Investigations of Vibronic Structure, Spin-Orbit Splittings and Magnetic Hyperfine Effects in the Electronic Spectra of Triatomic Molecules” in this volume.
5. B. O. Roos, M. Fülscher, P.-Å Malmqvist, M. Merchán, and L. Serrano-Andrés, see the chapter entitled “Theoretical Studies of the Electronic Spectra of Organic Molecules” in this volume.