G. P. Djotyan, V. M. Arutunyan, J. S. Bakos, and Z. Sörelei, “Nonlinear optics of the thin-film quasiwaveguide amplifier: applications to directional switching in the optical communication systems”, JTIT, vol. 1, no. 1-2, pp. 20–23, Jun. 2000, doi: 10.26636/jtit.2000.1-2.18.