Pendry, C. A., and F. Adema. “Polygala Obliqua Pendry, a New Species of Polygalaceae from Northern Thailand”. Thai Forest Bulletin (Botany), no. 41, Nov. 2014, pp. 41-44, https://li01.tci-thaijo.org/index.php/ThaiForestBulletin/article/view/24099.