Rare earth, trace element and stable isotope fractionation of carbonatites at Kruidfontein, Transvaal, South Africa,
Clarke, L. B., M. J. Le Bas, B. Spiro (1994) (1994),
Meyer, H. O. A. and Leonardos, O. H. (eds.), Kimberlites, Related Rocks and Mantle Xenoliths p. 236–251