@INBOOK {WIEN:1979, title = {Drought stress of cowpea and soybean under tropical conditions}, author = {Wien, H. C. and Litttleton, E. J. and Ayanaba, A. }, year = {1979}, type = {Stress physiology in rop plants, edited by H. Mussell and R. Staples, J. Wiley and Sons, New York}, }