Shen, Jianning; Miao, Yuxin; Cao, Qiang; Wang, Hongye; Yu, Weifeng; Hu, Shanshan; Wu, Haibing; Lu, Junjun; Hu, Xiaoyi; Yang, Wen; Liu, Fengyan (2014). "Estimating rice nitrogen status using active canopy sensor crop circle 430 in Northeast China". 2014 the Third International Conference on Agro-Geoinformatics. IEEE. pp. 1–7. doi:10.1109/Agro-Geoinformatics.2014.6910584. ISBN978-1-4799-4157-5.