@BOOK {NWEKE:1991,
title = {Production costs in the yam-based cropping systems of southeastern Nigeria: RCMP research monograph, No. 6},
author = {Nweke, F. and Ugwu, B. and Asadu, C. * and Ay, P. },
booktitle = {RCMP research monograph, No. 6},
year = {1991},
publisher = {International Institute of Tropical Agriculture (IITA)},
address = {Ibadan, Nigeria},
note = {RTB; Root and Tuber; Yam.; 29p.},
}