1. Agrochemical Methods of Soil Study, Ed. by A. V. Sokolov and D. L. Askinazi (Nauka, Moscow, 1965) [in Russian].
2. G. Blumenthal, S. Engels, I. Fitz, W. Haberditzl, K.‑H. Heckner, G. Henrion, R. Landsberg, W. Schmidt, G. Scholz, P. Starke, I. Wilke, and K-Th. Wilke, Anorganikum: Lehr- und Praktikumsbuch der Anorganischen Chemie mit Einer Einführung in die Physikalische Chemie (VEB Deutscher Verlag der Wissenschaften, Berlin, 1981; Mir, Moscow, 1984), Vol. 1.
3. N. G. Vasil’ev and F. D. Ovcharenko, “The chemistry of the surfaces of the acid forms of natural layer silicates,” Russ. Chem. Rev. 46, 775–788 (1977).
4. GOST (State Standard) R ISO 5725-5-2002: Accuracy (Trueness and Precision) of Measurement Methods and Results. Part 5. Alternative Methods for the Determination of the Precision of a Standard Measurement Method (Izd. Standartov, Moscow, 2002) [in Russian].
5. State Soil Map of Russia, Map 1 : 1 000 000. Explanatory Note to Sheet Q-41 (Vorkuta) (Komi Scientific Center, Ural Branch, Russian Academy of Sciences, Syktyvkar, 2011) [in Russian].