Literature

• Axelrod, F.S. 2015. A Systematic Vademecum to the Vascular Plants of Sint Eustatius. 179 pp.
• Howard, R.A. 1989. Dicotyledoneae - Part 3. In: Flora of the Lesser Antilles, Leeward and Windward Islands. 6: 658. Arnold Arboretum, Harvard University, Jamaica Plain, Massachusetts.
• The Plant List 2013. The Plant List version 1.1. [link]

Literature references linked to higher taxa

• Encyclopedia of Life. [link] (Apocynaceae)