Zhang, Ganghong, Wanlin Gao, Sha Tao, Lina Yu, Guofeng Zhang, and Xuan Luo. 2018. “Online Ultrasonic Terminal for Measuring Pig Backfat Thickness”. International Journal of Agricultural and Biological Engineering 11 (2):190-95. https://ijabe.migration.pkpps03.publicknowledgeproject.org/index.php/ijabe/article/view/3278.