A. A. Zvyagin, V. V. Slavin, and V. G. Piryatinskaya, Dynamical electric characteristics of a quantum paramagnet, Low Temp. Phys. 49, 1031–1036, (2023) [Fiz. Nyzk. Temp. 49, 1135–1140, (2023)] DOI: https://doi.org/10.1063/10.0020595.