1. Spedding, F.H. and Powell, J.E., Rare Earth Metals: Artilcle Collection, Komissarova, L.N. and Plushchev, V.E., Eds., Moscow: Inostr. Lit., 1957.
2. Spedding, F.H., Powell, J.E., and Wheelwright, E.J., Rare Earth Metals: Artilcle Collection, Komissarova, L.N. and Plushchev, V.E., Eds., Moscow: Inostr. Lit., 1957, pp. 176–178.
3. Gelis, V.M., Maslova, G.B., and Chuveleva, E.A., Radiokhimiya, 1998, vol. 40, no. 1, p. 55.
4. Gelis, V.M. and Maslova, G.B., Radiokhimiya, 1999, vol. 41, no. 5, p. 436.
5. Kharitonov, O.V., Chuveleva, E.A., and Firsova, L.A., Radiochemistry, 1998. Vol. 40, no. 2, p. 132.