1. H. Kirchmayr and C. A. Poldy, “Magnetic Properties of Intermetallic Compounds of Rare-earth Metals”, in Handbook of the Physcis and Chemistry of Rare Earths, Vol. 2, K. A. Gschneider and L. Eyring, eds., North-Holland Publishing Co., Amsterdam, 1979, p.55.
2. R. Verhoef, J. J. M. Franse, A. A. Menovsky, R. J. Radwanski, Ji Son-quan, Yang Fuming, H. S. Li, and J. P. Gavigan, J. de Physique 49, C8–565 (1988).
3. M. T. Hutchings, Solid State Phys. 16, 227 (1964).
4. P. Fulde and M. Loewenhaupt, Spin Waves and Magnetic Excitations, Vol.1, A. S. Borovik-Romanov and S. K. Sinha, eds., Elsevier Science Publishers, Amsterdam, 1988, p. 367.
5. G. J. Long, “An Introduction to Crystal-Field Effects in Magnetism”, in Supermagnets, Hard Magnetic Materials, G. J. Long and F. Grandjean, eds., Springer Science+Business Media Dordrecht, Dordrecht, 1991, p. 95.