1. Born, M.: Atomic Physics, 8th edn., pp. 24–27. Blackie & Sons, London (1969)
2. Cotton, F.A.: Chemical Applications of Group Theory, vol. 154, 2nd edn. Wiley, New York (1970)
3. Cotton, F.A., Wilkinson, G.: Advanced Inorganic Chemistry, vol. 102, 3rd edn. Wiley, New York (1972)
4. Coulson, C.A.: Valence 2nd edn, pp. 271–274. O.U.P., Oxford (1961)
5. DOI: : doi.org/10.1021/ja02261a002