Mardoyan, Gurgen R., and Trevor M. Benson. “Influence of Chirped DBR Reflector on the Absorption Efficiency of Multi-Nanolayer Photovoltaic Structures: Wavelength-Scale Analysis by the Method of Single Expression”. Journal of Telecommunications and Information Technology, vol. 69, no. 3, Sept. 2017, pp. 99-106, https://doi.org/10.26636/jtit.2017.120117.