@ARTICLE {EKANAYAKE:2003a, title = {Problems and perspectives of yam-based cropping systems in Africa}, author = {Ekanayake, I. J. and Asiedu, R. }, journal = {Journal of Crop Production}, year = {2003}, volume = {9}, number = {1-2}, pages = {531--558}, issn = {1092-678X}, note = {RTB; Root and Tuber; Yam}, }