1. Jørgensen CK (1962) Solid State Phys 13: 375
2. Jørgensen CK (1976) Gmelin's Handbuch der anorganische Chemie vol 39 B1 (Seltene Erden) p 17 Springer-Verlag, Berlin
3. Jørgensen CK (1991) Comments Inorganic Chem 12: 139
4. Jørgensen CK (1988) In: Gschneidner KA, Eyring L (eds) Handbook on the physics and chemistry of rare earths, North-Holland, Amsterdam, vol 11, p 197
5. Goldschmidt ZB (1978) In: Gschneidner KA, Eyring L (eds) Handbook on the physics and chemistry of rare earths, North-Holland, Amsterdam, vol 1, p 1