Zheng, Haibo, et al. “Automatic Detection of Sow Estrus Using a Lightweight Real-Time Detector and Thermal Images”. International Journal of Agricultural and Biological Engineering, vol. 16, no. 3, Aug. 2023, pp. 194-07, https://ijabe.migration.pkpps06.publicknowledgeproject.org/index.php/ijabe/article/view/7711.