1. : Nonlinear Optical Properties of Organic and Polymeric Materials, ACS Symp. Ser. No. 233, Washington 1983.
2. : Mathematical Techniques in Chemistry, Wiley, New York, 1975, p. 916.
3. See, e.g.: in : Quantum Electronics: A Treatise, Vol. 1, Academic Press, New York 1975.
4. Second and third order hyperpolarizabilities of organic molecules
5. in [1], p. 27.