London, Oxford University Press for the International Institute for Strategic Studies, 1999. Book call no. International 1997 Africa and the Middle East Volume 3 . Washington, U.S. Dept of the Interior and U.S. Geological Survey, 1999. The Mineral Industry of Sudan by Philip M. Mobbs, p LL1.
Book call no.
Boulder, CO, Westview Press, 1999. The author was the American Ambassador to Sudan in 1992-1995. Book call no. Binghamton, NY, CSA Publications, 1999. Gives details about the government of each country.