Variable-rate control system for UAV-based granular fertilizer spreader. - Cancan Song; Zhiyan Zhou; Ying Zang; Lingli Zhao; Wenwu Yang; Xiwen Luo; Rui Jiang; Rui Ming; Yu Zang; Le Zi; Qiuyang Zhu (Comput. Electron. Agric., 2021)