1. Allem, A. C., 1987. Manihot esculenta is a native of the Neotropics. Pl. Genet. Res. Newslett. 71: 22?24.
2. Allem, A. C., 1992. Manihot germplasm collecting priorities. Paper delivered at the international workshop on cassava genetic resources, CIAT, Cali, Colombia, 18?23 August, 1992. CIAT/IITA/IBPGR.
3. IBP Handbook;H. G. Baker,1970
4. Baker, H. G., 1971. Commentary: section 3. In: C. L. Riley, J. C. Kelley, C. W. Pennington & R. L. Rands (Eds.), Man Across the Sea: Problems of Pre-Columbian Contacts, pp. 428?444, University of Texas Press, Austin.
5. Beadle, G. W., 1977. The origin of zea mays. In: C. A. Reed (Ed.), Origins of Agriculture, pp. 615?635, Mouton, The Hague.