De Wilde, Willem J.J.O., and Brigitta E.E. Duyfjes. “Revision of Cyclocodon Griff. Ex Hook.F. & Thomson (Campanulaceae)”. Thai Forest Bulletin (Botany), no. 40 (November 24, 2014): 20–25. Accessed August 18, 2022. https://li01.tci-thaijo.org/index.php/ThaiForestBulletin/article/view/24122.