1. F.H. Spedding, A.H. Daane, The Rare Earths, Wiley, New York, 1961, pp. 77–125.
2. K.A. Geschneidner Jr., L.R. Eyring, Handbook on the Physics and Chemistry of Rare Earths, Vol. 1, North-Holland, Amsterdam, 1978, pp. 173–232.
3. Conversion of isotope compounds to metals by reduction-distillation methods