1. As the early review, S. Methfessel, D.C. Mattis, in: S. Flugge (Ed.), Handbuch der Physik, vol. 18, p. 1, Springer, Berlin, 1968.
2. See for example, P. Wachter, in: K.A. Gschneidner, L. Eyring (Eds.), Handbook on the Physics and Chemistry of Rare Earths, ch. 19, p. 507, North-Holland, Amsterdam, 1979; CRC Crit. Rev. Solid State Sci. 3 (1972) 189.
3. s‒f exchange interactions and magnetic semiconductors
4. For a recent review, see A. Mauger, C. Godart, Phys. Rep. 141 (1986) 52.
5. For example, see Refs. [1,2]. Furthermore, see p. 145 in Ref. [3] and p. 68 in Ref. [4].