VALCHOVSKI, I.; PETKOVA, Z.; KUTEV, V.; PCHELAROVA, H.; MARKOV, E.; KATSAROVA, A. Agrochemical Valuation of Different Subtypes Chernozem and Fertilization Optimization of Basic Crops. Bulgarian Journal of Soil Science, Agrochemistry and Ecology, Sofia, BG, v. 48, n. 3-4, p. 22–30, 2014. Disponível em: https://agriacad.eu/ojs/index.php/bjssae/article/view/2264.. Acesso em: 12 nov. 2026.