Ткачев, А. І., М. Л. Погребняк, and В. І. Кісленко. “Two-Frequency Dye Laser for Spectroscopy of Zinc Atoms in Triplet Rydberg States n3P012”. Visnyk of V.N. Karazin Kharkiv National University, Series “Radio Physics and Electronics”, no. 26, Jan. 2018, pp. 54-57, https://periodicals.karazin.ua/radiophysics/article/view/10177.