1. N.V. Arnautov, Standard samples of chemical composition of natural mineral matters, Institute of Geology and Geophysics SB USSR AS, Novosibirsk, 1990, p. 219 (in Russian).
2. Geochemistry of Rare Earth Elements;Balashov,1976
3. Geochemistry of Ferromanganese Nodules of Ocean;Baturin,1986
4. A.I. Vasil’eva, V.A. Bobrov, T.N. Grigor’eva, Features of the content and distribution of rare metals in ferromanganese formations (in Russian).