McMullin, Stepha, Maarten Nieuwenhuis, and Ramni Jamnadass. “Strategies for Sustainable Supply of and Trade in Threatened Medicinal Tree Species: A Case Study of Genus Warburgia”. Ethnobotany Research and Applications 12 (December 19, 2014): 671–683. Accessed October 19, 2021. https://ethnobotanyjournal.org/index.php/era/article/view/1000.