@BOOK {KRISTJANSON:2002a, title = {Genetically improved dualpurpose cowpea: assessment of adoption and impact in the dry savanna region of West Africa}, editor = {Kristjanson, P. and Tarawali, S. and Okike, I. and Singh, B. and Thornton, P. and Manyong, V. and Kruska, R. and Hoogenboom, G. }, year = {2002}, publisher = {International Institute of Tropical Agriculture (IITA)}, address = {Ibadan, Nigeria}, note = {ILRI Impact assessment series, No. 9}, }