Paul Clammer (2005). Sudan: the Bradt travel guide. Bradt Travel Guides. p. 5. ISBN 1-84162-114-5.
Kaj Vollesen (2005). Flora of the Sudan-Uganda border area east of the Nile: Catalogue of vascular plants, 2nd part, vegetation and phytogeography, Part 2. Kgl. Danske Videnskabernes Selskab. ISBN 87-7304-318-4. [1]