K. Aimaganbetov, S. Shegebay, A. Aldiyarov, S. Zhantuarov, and N. Tokmoldin, “Research of electrophysical properties of solar elements by impedance spectroscopy method using a specially designed low temperature microcryogenic measuring cell”, Rec.Contr.Phys., vol. 2021, no. 1, pp. 68–74, Apr. 2021.