Quan, Longzhe, Ci Chen, Yajun Li, Yajing Qiao, Dejun Xi, Tianyu Zhang, and Wenfeng Sun. 2019. “Design and Test of Stem Diameter Inspection Spherical Robot”. International Journal of Agricultural and Biological Engineering 12 (2):141-51. https://doi.org/10.25165/ijabe.v12i2.4163.