Aidoo, R. , Nimoh, F. , Bakang, J.-E.A. , Ohene-Yankyera, K. , Fialor, S.C. , Mensah , J.O. and Abaidoo , R.C. 2012. Estimation of Margins and Efficiency in the Ghanaian Yam Marketing Chain . Asian Journal of Agriculture and Rural Development. 2, 2 (Jun. 2012), 226–234.