@INBOOK {MORTIMORE:1997, title = {Cowpea in traditional cropping systems}, author = {Mortimore, M. J. and Singh, B. and Harris, F. and Blade, S. }, year = {1997}, type = {Advances in cowpea research}, pages = {99--113}, chapter = {9}, publisher = {International Institute of Tropical Agriculture (IITA); Japan International Research Center for Agricultural Sciences (JIRCAS)}, address = {Ibadan, Nigeria}, }