1. R. Kh. Aidinyan, Extraction of Clay from Soils: Brief Instruction (Giprovodkhoz, Moscow, 1960) [in Russian].
2. Yu. N. Blagoveshchenskii, E. A. Dmitriev, and V. P. Samsonova, Use of Nonparametric Methods in Soil Science (Moscow State Univ., Moscow, 1985) [in Russian].
3. V. I. Vernadsky, The Biosphere (Nauka, Moscow, 1990), Vol. 5, pp. 7–105.
4. Yu. N. Vodyanitskii, Chemistry and Mineralogy of Soil Iron (Dokuchaev Soil Science Inst., Moscow, 2002) [in Russian].
5. Yu. N. Vodyanitskii and V. V. Dobrovol’skii, Iron Minerals and Heavy Metals in Soils (Dokuchaev Soil Science Inst., Moscow, 1998) [in Russian].