"Effects of Poultry Manure on Soil Fertility, Growth and Yield of White Yam and Yellow Yam". University of Khartoum Journal of Agricultural Sciences 20, no. 3 (مارس 28, 2023). تاريخ الوصول مايو 25, 2026. https://onlinejournals.uofk.edu/uofkjas/article/view/1858.