Ruža, A., Dz. Kreita, M. Krotovs, S. Maļecka, and V. Stramkale. “Nitrogen Fertilizer Use Efficiency in Winter Wheat Trials”. ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference 1 (June 26, 2006): 232–237. Accessed May 7, 2024. https://journals.ru.lv/index.php/ETR/article/view/2011.