TUNGMUNNITHUM, DUANGJAI, MANIT KIDYOO, and CHUMPOL KHUNWASI. 2011. “Morphological Variations in Hoya Siamica Craib (Asclepiadaceae) in Thailand”. Tropical Natural History 11 (1):29-37. https://li01.tci-thaijo.org/index.php/tnh/article/view/103010.