Suwannarat, Sutthawee, Thanate Khaorapapong, and Mitchai Chongcheawchamnan. 2012. “Prediction of Oil Content in Fresh Palm Fruit Based on an Ultrasonic Technique”. Agriculture and Natural Resources 46 (2). Bangkok, Thailand:318-24. https://li01.tci-thaijo.org/index.php/anres/article/view/242817.