Berthold, Carl. “An Investigation into Improving the Germination Rates of Aloe Polyphylla Schönland Ex Pillans”. Sibbaldia: the International Journal of Botanic Garden Horticulture, no. 12 (October 29, 2014): 139–154. Accessed May 4, 2024. https://journals.rbge.org.uk/rbgesib/article/view/29.