E. I. Rashba and V. I. Sheka, Electric-Dipole Spin-Resonances, in: Landau Level Spectroscopy, (North Holland, Amsterdam) 1991, p. 131; https://arxiv.org/abs/1812.01721
Radwanski, R. J.; Michalski, R; Ropka, Z.; Błaut, A. (1 July 2002). "Crystal-field interactions and magnetism in rare-earth transition-metal intermetallic compounds". Physica B. 319 (1–4): 78–89. Bibcode:2002PhyB..319...78R. doi:10.1016/S0921-4526(02)01110-9.
Radwanski, R. J.; Michalski, R; Ropka, Z.; Błaut, A. (1 July 2002). "Crystal-field interactions and magnetism in rare-earth transition-metal intermetallic compounds". Physica B. 319 (1–4): 78–89. Bibcode:2002PhyB..319...78R. doi:10.1016/S0921-4526(02)01110-9.