1. A. Sh. Galstyan, Enzymatic Activity of Armenian Soils (Aiastan, Yerevan, 1974) [in Russian].
2. E. V. Dadenko and K. Sh. Kazeev, “The Effect of Different Durations of Sample Storage on the Enzymatic Activity of Chernozem,” Izv. VUZov. Severo-Kavkazskii Region. Estestven. Nauki. Suppl., No. 6, 61–65 (2004).
3. V. A. Demkin, T. S. Demkina, A. O. Alekseev, et al., Paleosols and Climate of the Lower Volga Steppes in the I-IV Centuries AD (ONTI PNTs RAN, Pushchino, 2009) [in Russian].
4. D. G. Zvyagintsev, “Immobilized Enzymes in Soils,” in Microbial Metabolites (Izd. Mosk. Gos. Univ., Moscow, 1979), pp. 31–46 [in Russian].
5. K. Sh. Kazeev, S. I. Kolesnikov, and V. F. Val’kov, Biology of the Soils of Southern Russia (Rostov-on-Don, 2004) [in Russian].