Cui, Siyuan, et al. “Effects of Tillage on Soil Nitrogen and Its Components from Rice-Wheat Fields in Subtropical Regions of China”. International Journal of Agricultural and Biological Engineering, vol. 15, no. 3, June 2022, pp. 146-52, https://ijabe.migration.pkpps03.publicknowledgeproject.org/index.php/ijabe/article/view/5661.