Morris, Leigh, and Laura Cohen. “The Development of the Royal Botanic Garden Edinburgh ‘Certificate in Practical Horticulture’”. Sibbaldia: the International Journal of Botanic Garden Horticulture, no. 8 (November 13, 2010): 165-178. Accessed October 22, 2020. https://journals.rbge.org.uk/rbgesib/article/view/144.