Torrefiel, Jay T., and Inocencio E. Buot Jr. 2017. “Hoya carandangiana, Hoya bicolensis, and Hoya camphorifolia (Apocynaceae) Species Delineation: Insights from Leaf Architecture”. The Thailand Natural History Museum Journal 11 (1):35-44. https://li05.tci-thaijo.org/index.php/thnhmj/article/view/1850.