Ibrahim, H. M., A. R. Alshaibani, and A. N. A. Al-Gifri. “Epidermal Properties of Aloe Vacillans Forsskål Leaf and Its Taxonomical Significance in Classifying Its Two Forms”. PSM Biological Research, vol. 6, no. 3, July 2021, pp. 76-83, https://psmjournals.org/index.php/biolres/article/view/562.