1. A. Ya. Antykov and A. Ya. Stomorev, Soils of the Stavropol Region and Their Fertility (Stavropol, 1970) [in Russian].
2. E. V. Arinushkina, Handbook on the Chemical Analysis of Soils (Mosk. Gos. Univ., Moscow, 1970) [in Russian].
3. E. A. Afanas’eva, Water-Salt Regime of Ordinary and Southern Chernozems in Southeastern Regions of European USSR (Nauka, Moscow, 1980) [in Russian].
4. L. G. Balaev and P. V. Tsarev, Loess Sediments in the Central and Eastern Ciscaucasia (Nauka, Moscow, 1964) [in Russian].
5. A. A. Velichko and T. A. Khalcheva, “Late-Pleistocene Loesses and Their Distribution,” in Paleogeography of the Europe for the Last Hundred Thousands of Years: an Atlas-Monograph (Nauka, Moscow, 1982), pp. 70–74 [in Russian].