1. Analytical Support for Monitoring the Humus Status of Soils: Methodological Recommendations (Rossel’khozakademiya, Pochv. Inst. im. V. V. Dokuchaeva, 1993) [in Russian].
2. R. A. Afanas’ev, “Agrochemical support for precision farming,” Probl. Agrokhim. Ekol., No. 3, 46–53 (2008).
3. R. A. Afanas’ev, “Methodology of field experiments on differentiated use of fertilizers in precision farming conditions,” Probl. Agrokhim. Ekol., No. 1, 38–44 (2010).
4. J.-B. Wei, D.-N. Xiao, X.-Y. Zhang, and X.-Y. Li, “Topography and land use effects on the spatial variation of soil organic carbon: a case study in a typical small watershed of the black soil region in northeast China,” Eurasian Soil Sci. 41 (1), 39–47 (2008).
5. S. E. Vitkovskaya, “Spatial variability of fertility parameters of soddy-podzolic soil in field experiments,” Agrofizika, No. 2, 19–25 (2011).