Fitio, Volodymyr     Analysis of light wave diffraction and amplification by reflection grating operating in the second-order Bragg regime. 2. Reflectivity and spectral characteristics of a grating [Текст] / Volodymyr Fitio, Tatiana Smirnova // Journal of the Optical Society of America B. Optical Physics. — 2012. — № 5. — P. 944-949.