I. P. Zharkov, A. N. Ivaschenko, Sаfrоnоv V. V., Sеlivanov A. V., and Sоlоnetsky A. G., “Extension of Temperature Control Interval in Liquid-Flow Helium Cryostats”, Ukr. J. Phys., vol. 63, no. 10, p. 916, Oct. 2018.