1. For an overview see for example: In Encyclopedia of Computational Chemistry, Ed.; Wiley: Chichester, 1998, Vol. 1;p. 615, and references therein.
2. For an overview see for example: Configuration Interaction in ref. 1, but p. 485 and references therein.
3. Adv Chem Phys;Roos,1987
4. ; The Conservation of Orbital Symmetry; Verlag Chemie, Academic Press: Weinheim, 1970.
5. Orbital Symmetry and Reaction Mechanism; Springer-Verlag: Berlin, 1992.