1. E. V. Arinushkina, Manual on the Chemical Analysis of Soils (Moscow State University, Moscow, 1970) [in Russian].
2. J. C. Bailar, Jr. and D. H. Busch, “A general review of coordination compounds,” in Chemistry of Coordination Compounds (IL, Moscow, 1960), pp. 7–86.
3. J. R. van Wazer, Phosphorus and Its Compounds (Interscience, New York, 1958–1961).
4. A. A. Grinberg, Introduction to Chemistry of Complex Compounds (Khimiya, Leningrad, 1971) [in Russian].
5. O. B. Dudkin, Geochemistry and Regularities of Phosphorous Concentration in Alkaline Massifs of Kola Peninsula (Nauka, Leningrad, 1977) [in Russian].