Cubey, Robert, and Martin F Gardner. “A New Approach to Targeting Verifications at the Royal Botanic Garden Edinburgh”.
Sibbaldia: the International Journal of Botanic Garden Horticulture, no. 1 (October 31, 2003): 19–23. Accessed April 12, 2025.
https://journals.rbge.org.uk/rbgesib/article/view/90.