1. L. N. Aleksandrova and O. V. Yurlova, “Methods for the Determination of Humus in Arable Soddy-Podzolic Soils (with Soils of the Leningrad Oblast as an Example),” Pochvovedenie, No. 8, 21–28 (1984).
2. L. G. Bakina, T. A. Plotnikova, N. E. Orlova, and L. I. Egorova, “Effect of Different Lime Rates on the Humus Status of Clayey Soddy-Podzolic Soil,” in Fertilization in High-Input Farming Systems in the Northwestern Russian Federation (Leningrad, 1987), pp. 14–21 [in Russian].
3. L. G. Bityutskaya and L. I. Egorova, “Effect of Liming on the Composition and Properties of Humus in the Clay Loamy Soddy-Podzolic Soil of the Novgorod Agricultural Experimental Station,” in Proceedings of the Scientific Conference “Dokuchaev Soil Science: 100 Years in the Agriculture,” Leningrad, 1983 (Leningrad, 1983), pp. 24–25 [in Russian].
4. B. A. Dospekhov, Methods of Field Experiments (Kolos, Moscow, 1973) [in Russian].
5. F. R. Zaidel’man, Ecological-Ameliorative Soil Science of Humid Landscapes (Agropromizdat, Moscow, 1991) [in Russian].