1. Badi KHM, Ahmed AE, Bayoumi MS (1989) The forest of the Sudan. Forest National Corporation, Khartoum
2. Ballal ME (1991) Acacia senegal: a multi-purpose tree species for the arid and semi-arid tropics. M.Sc. theses, University of Wales, UK
3. Ballal ME (2002) Yield trends of gum Arabic from Acacia senegal as related to some environmental and managerial factors. Ph.D. thesis, University of Khartoum, p. 105
4. Ballal ME, ElSiddig EA, El Fadl MA, Luukkanen O (2005) Gum Arabic yield in differentially managed Acacia senegal stands in western Sudan. Agrofor Syst 63:237–245
5. Bashir M (2001) Sudan country study on Biodiversity. Silver Star press, Khartoum