Chen, Haibo, Yubin Lan, Bradley K Fritz, W. Clint Hoffmann, and Shengbo Liu. 2021. “Review of Agricultural Spraying Technologies for Plant Protection Using Unmanned Aerial Vehicle (UAV)”. International Journal of Agricultural and Biological Engineering 14 (1). Beijing, China:38-49. https://ijabe.org/index.php/ijabe/article/view/5714.