@BOOK {NWEKE:1990, title = {Methodologies and data requirements for cassava systems study in Africa: COSCA working paper, No. 4}, author = {Nweke, F. and Lynam, J. * and Prudencio, C. Y. }, series = {COSCA working paper}, year = {1990}, number = {4}, publisher = {International Institute of Tropical Agriculture (IITA)}, address = {Ibadan, Nigeria}, note = {RTB; Root and Tuber; Cassava.; 46p.}, }