Mohammed, A. S., Adamu, A. K., Mu’azu, S., Nafiu, M. I., and Nura, S. “Effect of Crossability in Improving Some Selected Cowpea (Vigna Unguiculata [L.,] Walp) Varieties”. International Journal of Science for Global Sustainability, vol. 6, no. 2, July 2020, p. 8, doi:10.57233/ijsgs.v6i2.108.