Augustine BB, Godfre W. Effect of different phosphorus levels on four cowpea (Vigna unguiculata Walp L.) varieties for grain and fodder yield in Upper East Region of Ghana. Arch. Agric. Environ. Sci. [Internet]. 2019 Jun. 10 [cited 2026 Apr. 2];4(2):242-8. Available from: https://aesacademy.org/journals/index.php/aaes/article/view/aaes-04-02-018