@INBOOK {SINGH:2002e, title = {Cowpea varieties for drought tolerance}, author = {Singh, B. and Matsui, T. }, year = {2002}, type = {Challenges and opportunities for enhancing sustainable cowpea production:}, pages = {287--300}, note = {Proceedings of the World Cowpea Conference III held at the International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria, 4-8 September 2000}, }