A. V. Pavlenko, S. V. Kara-Murza, A. P. Korchikova, A. A. Tikhii, D. V. Stryukov, N. V. Kovtun, “Structure and optical characteristics of barium–strontium niobate films on Al$_2$O$_3$ substrates”, Optics and Spectroscopy, 126:5 (2019), 568–572; Optics and Spectroscopy, 126:5 (2019), 487–491
