Djotyan, Gagik P., et al. “Nonlinear Optics of the Thin-Film Quasiwaveguide Amplifier: Applications to Directional Switching in the Optical Communication Systems”. Journal of Telecommunications and Information Technology, vol. 1, no. 1-2, June 2000, pp. 20-23, https://doi.org/10.26636/jtit.2000.1-2.18.