Literature

• Axelrod, F.S. 2015. A Systematic Vademecum to the Vascular Plants of Sint Eustatius. 179 pp.
• Boldingh, I. 1909. The flora of the Dutch West Indian Islands St. Eustatius, Saba and St. Martin. 321 pp. E.j. Brill., Leiden.
• Fingal, J.F. 1984. Rubiaceae. Flora of the Netherlands Antilles 3: 378-409.
• Rojer, A. 1997. Biological Inventory of Saba. 87 pp. CARMABI Foundation, Curaçao.
• Rojer, A. 1997. Biological inventory of Sint Eustatius. CARMABI Foundation, Curaçao.
• The Plant List 2013. The Plant List version 1.1. [link]
• WCSP 2017. World Checklist of Selected Plant Families. Facilitated by the Royal Botanic Gardens, Kew. [link]

Literature references linked to higher taxa

• Encyclopedia of Life. [link] (Rubiaceae)