Zhou, Wenqi, et al. “Structure Optimization of Cam Executive Component and Analysis of Precisely Applying Deep-Fertilization Liquid Fertilizer”. International Journal of Agricultural and Biological Engineering, vol. 12, no. 4, Aug. 2019, pp. 104-9, https://ijabe.migration.pkpps06.publicknowledgeproject.org/index.php/ijabe/article/view/4865.