1. L. Schlapbach, Topics in Applied Physics, vol. 67, Springer-Verlag, Berlin, 1992.
2. J.S. Abell, in: K.A. Gschneidner Jr., E. LeRoy (Eds.), Handbook on the Physics and Chemistry of Rare Earth, vol. 12, North-Holland, Amsterdam, 1989, p. 1.
3. L. Schlapbach, Topics in Applied Physics, vol. 63, Springer-Verlag, Berlin, 1988.
4. K.H.J. Buschow, in: K.A. Gschneidner Jr., E. LeRoy (Eds.), Handbook on the Physics and Chemistry of Rare Earth, vol. 6, North-Holland, Amsterdam, 1984, p. 1.
5. K.H.J. Buschow, H.H. van Mal, in: M.S. Whittingham, A.J. Jacobson (Eds.), Intercalation Chemistry, Academic Press, New York, 1982, 405 pp.