“Nitrogen Nutrition of Cowpeas (Vigna Unguiculata) Effects of Timing of Inorganic Nitrogen Applications on Nodulation, Plant Growth and Seed Yield”. Tropical Agriculture 58, no. 1 (January 30, 1981). Accessed July 15, 2024. https://journals.sta.uwi.edu/ojs/index.php/ta/article/view/2821.