@ARTICLE {NG:1983a, title = {Special techniques assist in quality seed production of sweet potato, yam and cocoyam}, author = {Ng, S. Y. C. }, journal = {Paper presented at the Global Workshop on Root and Tuber Crops Propagation, 12-16 September 1983, CIAT, Cali, Colombia}, year = {1983}, note = {RTB; Root and Tuber}, }