Geng, L., Y. Hu, J. Xi, and Y. Liu. “Detection on the Fertility of Hatching Eggs Based on Heart Rate Threshold”. American Scientific Research Journal for Engineering, Technology, and Sciences, vol. 53, no. 1, Feb. 2019, pp. 49-63, https://asrjetsjournal.org/index.php/American_Scientific_Journal/article/view/4711.