Aliyu, A., Shelleng, B. and Usman, J. 2018. FARM LEVEL EFFICIENCY OF RUBBER AS A PERENNIAL CROP USING COBB-DOUGLASS PRODUCTION FRONTIER. International Journal of Research -GRANTHAALAYAH. 6, 7 (Jul. 2018), 65–75. DOI:https://doi.org/10.29121/granthaalayah.v6.i7.2018.1284.