1. Studies on yield and tuber characters of greater yam, Dioscorea alata L;Abraham;J. Root Crops,1984
2. Optimising sett size and sett multiplication ratio for ware tuber production in Guinea yams;Akoroda;Field Crops Res.,1985
3. Effects of cutting seed tubers on number of stems and tubers and tuber yields of several potato varieties;Allen;J. Agric. Sci.,1979
4. Plant population and crop yield;Baker;Nature,1964
5. Bremner, P.M., El-Saeed, A.K., 1963. The significance of seed size and spacing. In: Invins, J.D., Milthorpe, F.L. (Eds.), The Growth of the Potato. Proceedings of the 10th Easter School in Agricultural Science, University of Nottingham. Butterworths, London, pp. 267–280.