Baltazar, Alcona Mae P., and Inocencio E. Buot, Jr. 2019. “Resolving Taxonomic Confusion between Hoya cumingiana Decne. and Hoya densifolia Turcz. (Apocynaceae) using Leaf Architectural Analysis”. The Thailand Natural History Museum Journal 13 (2):77-89. https://li05.tci-thaijo.org/index.php/thnhmj/article/view/1852.