1. Handbook on the Physics and Chemistry of Rare Earths, ed. K. A. Gschneidner Jr. and L. Eyring, North-Holland, Amsterdam, 1979, vol. 2;
2. W. E. Wallace , Rare Earth Intermetallics, Academic Press, New York, 1973, and references therein.
3. J. C. Thompson , Electrons in Liquid Ammonia, Clarendon Press, Oxford, 1976;
4. Metal-ammonia solutions. 13. Solutions of lanthanoid metals
5. Catalytic activity of lanthanide (Eu and Yb)-promoted catalyst systems