Baas, Pieter, and Peter Hovenkamp. “Obituary : Jan Frits Veldkamp (1941–2017)”. Sibbaldia: the International Journal of Botanic Garden Horticulture, no. 16 (July 26, 2018): 5–6. Accessed June 26, 2025. https://journals.rbge.org.uk/rbgesib/article/view/242.