E. Asiedu, P. Akowuah-Adusei, B. Asafo-Adjei, H. Adu-Dapaah, and O. Danquah, “Causes of differences in seed quality among cowpea (<i>Vigna unguiculata</i> (L.) Walp) cultivars”, Ghana J. Agric. Sci, vol. 42, no. 1-2, Oct. 2010.