Doktorovich, I. V., I. M. Fodchuk, V. K. Butenko, V. N. Godovanyuk, V. V. Ryukhtin, and V. G. Yuryev. “Influence of Radiation Flux Instability of Mercury Lamps on Instrument Calibration”. Technology and Design in Electronic Equipment, no. 1, Feb. 2006, pp. 54-57, https://www.tkea.com.ua/index.php/journal/article/view/TKEA2006.1.54.