1. B. I. Sturman and V. M. Fridkin, The Photovoltaic and Photorefractive Effects in Noncentrosymmetric Materials (Gordon and Breach Philadelphia, 1992).
2. Photorefractive Materials and Their Applications, Ed. by P. Günter and J.-P. Huignard (Springer-Verlag, Berlin, 1988), Vols. I, II.