@ARTICLE {MULEBA:1991a, title = {Use of successional sowing in evaluating cowpea (Vigna unguiculata) adaptation to drought in the Sudan savannah zone. 1. Seed yield response}, author = {Muleba, N. and Mwanke, N. and Drabo, I. *}, journal = {Journal of Agricultural Science, Cambridge}, year = {1991}, volume = {116}, pages = {73--81}, }