Tunyaporn Sirilert, Anuvat Jangchud, Phaisan Wuttijumnong, and Kamolwan Jangchud. 2006. “Effect of Coating on Doughnut Cake Preference using R-index”. Agriculture and Natural Resources 40 (1). Bangkok, Thailand:240-46. https://li01.tci-thaijo.org/index.php/anres/article/view/243555.