1. Korcher S.C, Tropical Crops, a text book of economic Macmillan Publishers, (New Delhi, India, 1981)
2. David G. and Adamu J., Crops of the Drier Region of Tropics, (Longman Press. 1991)
3. Helfand S.M.: Farm Size and the Determinant of Production Efficiency in the Brazilian Centre-West Proceeding of the 25th International Conference of Agricultural Economics, Durban, South Africa, 16th-22nd August, 2003, Pp 605-612, (2003)
4. Muhammad B.
Economic Analysis of Cotton Production in Gassol Local Taraba State. Unpublished PGD Thesis Agricultural Economics, Federal University of Technology, Yola, (2007)
5. CBN: Statistical Bulletin Vol. 18, December (2007)