Pichai Kongpitak, Pongtep Akratanakul, & Weerawan Amornsak. (1990). The study of Relationship Between Using Production Technology and Quantity of Pollen to Royal Jelly Production. Agriculture and Natural Resources, 24(3), 268–277. retrieved from https://li01.tci-thaijo.org/index.php/anres/article/view/242160