N. Mironova-Ulmane, A. I. Popov, G. Krieke, A. Antuzevics, V. Skvortsova, E. Elsts, and A. Sarakovskis, Low-temperature studies of Cr³⁺ ions in natural and neutron-irradiated Mg-Al spinel, Low Temp. Phys. 46, (2020) [Fiz. Nizk. Temp. 46, 1359-1364, (2020)] DOI: https://doi.org/10.1063/10.0002467.