1. See for example, R. W. Boyd, Nonlinear Optics (Academic, San Diego, 1992).
2. See for example, P. N. Prasad and D. Williams, Introduction to Nonlinear Optical Effects in Molecules and Polymers (Wiley, New York, 1991).
3. T. Verbiest, D. M. Burland, M. C. Jurich, V. Y. Lee, R. D. Miller, and W. Volksen, Science 268, 1604 (1995).
4. J. F. Nicoud and R. J. Twieg, in Nonlinear Optical Properties of Organic Molecules and Crystals, Vol. 1, edited by D. S. Chemla and J. Zyss (Academic, Orlando, 1987).
5. G. Wagnière, Linear and Nonlinear Optical Properties of Molecules (VCH, Weinheim, 1993).