Alidu, M. S. “Genetic Variability for Flowering Time, Maturity and Drought Tolerance in Cowpea [Vigna Unguiculata (L.) Walp.]: A Review Paper”. Journal of Agriculture and Ecology Research International 17, no. 2 (March 15, 2019): 1-18. Accessed August 13, 2020. https://journaljaeri.com/index.php/JAERI/article/view/30044.