Soil and Water Resources Survey of the Sokoto Valley. General Legend of the Semi-Detailed Soil Map of the Rima Floodplain. Area between Wurno And Bunza mapped at scale 1:20,000 (18 sheets). Area between Sabin Birni and Wurno mapped at Scale 1:50,000 (3 Sheets).
Northern Nigeria and United Nations Development Programme Special Fond.